Population

International Encyclopedia of the Social Sciences
COPYRIGHT 2008 Thomson Gale

Population

The articles under this heading provide an overview of the field of population. Specific topics directly within the field of demography are reviewed in Fertility; Migration; Mortality; Nuptiality. Methods used for the study of population are described in Census; Life Tables; Sample Surveys; Statistics; Survey Analysis; Vital Statistics. Other material directly relevant to the study of population will be found in Capital, Human; Epidemiology; Fertility Control; Food, article on World Problems; Genetics, article on Demography and Population Genetics; Labor Force; Literacy; Public Health; Social Behavior, Animal, article on The Regulation of Animal Populations. Also relevant are the biographies of Bertillon; Graunt; Lotka; Malthus; Petty; Sundt; StJssmilch; WlCksell; WlLlcox.

Demography is the quantitative study of human populations. Its basic materials are censuses, vital statistics, and, increasingly, sample surveys. Its central concerns are the measurement and discovery of uniformities in the basic processes of human birth, death, population movement, and population growth; these phenomena are treated in both their socioeconomic and their biological contexts. The methods of demography are empirical and statistical and make as much use of advanced mathematics as those of any branch of the social sciences. Like anthropology and psychology, demography bridges the social and biological sciences.

The word “demography” was apparently first used by Achille Guillard in his Elements de statistique humaine, ou demographie compare in 1855. Its Greek origins are demos (people) and graphein (to draw, describe). Until recently, the word had not attained general usage among English-speaking peoples, and those using it were frequently the victims of typographers and casual audiences who insisted on confusing it with “democracy.” The most widely used textbook on population problems in the United States during the period from 1930 to 1960 does not mention the word in the first three editions and refers to it only casually in the fourth and fifth (Thompson & Lewis 1930). However, the word is gaining both wider usage and wider meaning as describing the scientific aspect of population study.

Formal demography A distinction is commonly made between “formal,” or “pure,” demography and broader population studies. Formal demography is a well-defined, technical subject with a highly developed mathematical methodology. It is concerned primarily with the measurement and analysis of the components of population change, especially births, deaths, and, to a smaller extent, migration. It is concerned with population structure—that is, the age, sex, and marital composition of the population—as it contributes to the understanding of population change.

Formal demography has provided some of the most fruitful uses of mathematical models in the social sciences. These include the construction of life tables, which provide the terms within which life insurance and social security systems must operate; intrinsic rates of reproduction and other sophisticated measures of natality, which have contributed much to the understanding of the secular decline of birth rates in the West and their fluctuations after World War ii; stable population analysis, which has provided methods of estimating birth rates and rates of population growth in the absence of reliable vital statistics and often with grossly inaccurate census data; and population projections, based on the analysis of trends in the components of population change. Such projections are in great demand for purposes of economic development, market research, city planning, educational planning, estimating future labor supply, and numerous other approaches to measuring people as producers and consumers.

For actuarial purposes, demography is usually defined in the narrow sense of formal demography (Cox 1950). This definition also prevails in certain European countries, notably Italy.

Broader usage. A broader and increasingly popular usage of the term “demography” includes studies of demographic variables in their social contexts as well as their biological contexts. In this approach, demographic changes are viewed as part of, and as both cause and effect of, their social environment. Demographic analysis has also come to mean “not only the statistical manipulation of population data, but more important, the study of such data as a method of solving empirical problems” (Spengler & Duncan [1956a] 1963, p.xiii).

In addition to the components of population change, demographic variables are rather arbitrarily assumed to include those mass measurements of population that are commonly enumerated in population censuses: the size and distribution of the population, its biological composition by age and sex, and certain of its more measurable socioeconomic characteristics. Among these variables, data on population size, geographical distribution (including rural-urban), age-sex composition, and marital status are generally considered to be more specifically the subject matter of demography. Other socioeconomic characteristics, such as race, language, religion, education, occupation, and income, are studied in their own right and often in relation to group differences in birth rates, death rates, and migration.

The broader definition of demography inevitably involves interdisciplinary aspects, since demographers and other social scientists may study human populations in relation to other variables. Thus, a study of rural-urban migration may be considered demographic if it is primarily concerned with measurement and quantitative uniformities, economic if it is concerned with economic causes and effects, and sociological if it deals with sociological causes and effects. There is no firm line of demarcation, nor should one be expected. Beyond the specific discipline of formal demography there is no distinguishing criterion of demography as such, other than its involvement in quantitative measures of human populations. Thus, it can be said that the subject matter of demography includes those population theories that are based on quantitative observation and generalization, but not those that are formulated a priori at a more abstract and polemical level.

The development of demography

Censuses in various forms were conducted early in human history. A Roman census was taken under Caesar Augustus the year Christ was born (thus forcing Joseph and Mary to journey to Bethlehem to be enrolled in the place of their ancestry); and a major census was conducted in China in the year 2 A.D., during the Han Dynasty.

While such scattered censuses are of great interest for historical demography, modern censuses usable for scientific pursuits are essentially of nineteenth-century origin. Regular decennial censuses were initiated in the United States in 1790 and in France and England in 1801. Important exceptions are the population registers in Scandinavia, which date back to 1686 in Sweden and 1769 in Denmark.

Origins in vital statistics

Empirical demography began in the context of vital statistics with the work of John Graunt. His Natural and Political Observations Upon the Bills of Mortality, published in 1662, is a study of current reports on burials and christenings for a population of about 500,000 persons in the vicinity of London. The very title of this early work illustrates the fact that demography has roots in both biological and social inquiries. In the 1670s, William Petty built on Graunt’s work to write a treatise on what he described as “political arithmetick.” Gradually demography was absorbed into the new and more general study of statistics to the point that, in the United States, for example, concern about the accuracy and implications of vital statistics in the city of Boston led to the establishment of the American Statistical Association in 1839.

The line of succession in the biostatistical tradition of demography is a notable one (see Lorimer 1959). Interest in biostatistics led to attempts to explain population change in terms of mathematical processes, particularly logistic curves. Population change was conceived in terms of mechanical models by nineteenth-century researchers such as Adolphe Quetelet and Pierre Francois Verhulst and in biological terms by Pearl and Reed (1920), Alfred J. Lotka (1925), and G. Udny Yule (1925). While mechanical and biologically deterministic models did not ultimately prove convincing, they did lead to major developments in the statistical analysis of the processes of birth and death. Outstanding among these were Lotka’s contributions in computing reproduction rates and intrinsic, or true, rates of natural increase, holding constant the age structure of the population. The use of mathematical models, both stochastic and deterministic, has enjoyed a rebirth in demography, perhaps because of the vogue of model-building in social sciences generally, and certainly because of the capabilities of modern computer technology.

Malthusian theory

The economic approach to demography is commonly traced to the work of Thomas Malthus, although he readily admitted the contributions of his predecessors. His Essay on the Principle of Population, first published in 1798, is undoubtedly the most discussed work in the field of demography. While he modified his position in successive versions of the volume, Malthus held the general view that population tends to increase faster than the means of subsistence and thus to absorb all economic gains, except when checked by moral restraint, vice, and misery.

Malthus’ influence was enormous, but his view was later challenged in three ways. First, during the nineteenth century economic growth far outdistanced population growth among European peoples, resulting in rising levels of living. Second, despite rises in the level of living, birth rates declined, first in France and Sweden, and by 1880 in western Europe generally. Finally, liberals and Marxists challenged the Malthusian view by asserting that poverty was the result of unjust social institutions rather than of population growth. Regardless of the validity of this argument, it caused population study to be associated with the conservative social philosophy of Malthus, an association which retarded the growth of demography as a scientific discipline. As one author says,

The marriage of demography and economics while both were immature—“Parson” Malthus officiating— resulted in a stormy and unfruitful union. Both the dynamics of interactions among economic factors and the dynamics of vital trends in relation to population structure were long neglected in a hasty synthesis that placed undue emphasis on the relation of population to resources and the corollary theory of a hypothetical fixed “optimum.” This led to the fallacious assumption that increase of population is necessarily advantageous in a country with low density of population and to an unwarranted pessimism about the possibilities of economic progress in densely populated countries. (Lorimer 1957, p. 21)

Dissatisfaction with the Malthusian approach led to the divorce of demography from economics and to a continuing suspicion among some economists that demography overemphasizes the force of population growth and that population control in underdeveloped areas is in some way a diversion from, and even a threat to, the central purpose of economic development. Therefore, the economics of population change in the contemporary world has not received the attention that its importance would seem to merit, although it has not been entirely neglected. Now largely separated from economics, demography in the English-speaking world is commonly taught as a branch of sociology.

The birth rate in Western society

In its sociological aspects, population study emerged as a science in the 1920s and 1930s. Up to that time, births, deaths, and natural increase had generally been regarded as biologically given, exogenous both to the economy and to the social system. But by the interwar period, the general reduction of the birth rate in Western society had become highly visible and was the principal focus of demographic inquiry. Demographic studies demonstrated the social, as opposed to the biological, correlates and determinants of the decline in the birth rate.

Thus, empirical studies showed that the decline was not the result of biological sterility but of voluntary restriction of births, predominantly by methods requiring a high level of motivation. It is perhaps not widely known even today that reduction of the birth rate through contraception was initially and predominantly the result of “male” methods, specifically the practice of coitus interruptus and, later, the use of the condom; the principal “female” method of birth control was abortion [seeFertility Control]. The feminist birth control movement was noisy, often courageous, and certainly psychologically important, but there is little empirical evidence that the methods it advocated or the services it provided ever played a large part in the reduction of the birth rate in the Western world. In much of the Western world the chief methods of birth control are still coitus interruptus and abortion, although these are being increasingly replaced by new methods that have become generally available only since 1960.

Another major concern of demographers was “differential fertility,” that is, the general observation that birth control was first adopted by the more urbanized, the better educated, and the upperincome groups, with consequent rural–urban, educational, and class differences in birth rates. Demographers were reluctant to do more than measure these differences, but their observations reinforced concern about population “quality,” since class differences in natality clearly seemed to favor the reproduction of the socially and economically unsuccessful, and possibly also the genetically inferior.

The obvious role of social environment and voluntary control in the reduction of the birth rate gave rise to a new realization that birth and death rates, like migration, are effects as well as causes of social changes–dependent as well as independent variables with reference to the society in which they occur. Some felt that the existing trends were disturbing and even alarming, threatening “race suicide,” on the one hand, and deterioration of “quality,” on the other.

The reaction to the declining birth rate was strongest in the totalitarian countries that for nationalistic reasons adopted “pronatalist” population policies. These policies included such measures as propaganda for larger families, family allowances, suppression of induced abortion, marriage loans with deductions for each child born within the period of repayment, “motherhood medals” for parents of large families, and various privileges in taxation and in the social insurance schemes. Prior to World War ii such policies were adopted in fascist Italy, Nazi Germany, the Soviet Union, and Japan. Some of these measures, without the nationalistic overtones, were also adopted in France and Sweden [seePopulation, article onPopulation Policies].

In the English-speaking countries reaction to the declining birth rate was slower. In the United States the problem was given intensive study by the National Resources Committee (U.S. National Resources…1938). In Great Britain and Canada family allowances were adopted after World War ii; and in Great Britain a Royal Commission on Population was created and issued a report that is a landmark in British thinking on this point (Great Britain 1949–1954).

The effect of these pronatalist policies is controversial. The only clear cases of moderate success are rises in birth rates achieved in Nazi Germany and in the Soviet Union. In Germany the suppression of abortion and the promotion of earlier marriages and childbirth by marriage loans were contributing factors in the rise in the birth rate from 14.7 in 1933 to 20.3 in 1939 (Kirk 1942; Demographic Yearbook 1948, p. 262). But a substantial part of this increase was almost certainly due to the general improvement in economic conditions, especially the reduction of unemployment. In the Soviet Union the suppression of abortion was especially successful in raising birth rates in the cities, because abortion had formerly been legal and had even been provided as a health service of the state. In the mid-1950s abortion was again legalized and the birth rate in the Soviet Union is now quite low. In the period since World War n, French observers have expressed the view that family allowances have contributed to maintaining a higher birth rate in that country.

Theory of the vital revolution

In Western countries there were important regularities in the declines in death rates and birth rates, whether viewed in time or space. The spread of declines, first in death rates and later in birth rates, is a well-documented example of cultural diffusion. From these regularities were derived a number of general propositions concerning the sequence of demographic developments in the modern world Taken together, these propositions have come to be called the “theory of the vital revolution,” or the “theory of the demographic transition.”

According to this theory, in premodern societies both birth and death rates are high; reproduction is inefficient because it is necessary to have high, relatively unrestricted natality in order to match the waste of a high death rate. The initial effect of modernization is a fall in the death rate, apparently owing to higher levels of living and to the introduction of epidemic controls and other elementary public health measures. Without a comparable decline in the birth rate, there is a growing margin of births over deaths and an accelerating rate of population growth. At a later stage of socioeconomic development, with the achievement of general literacy, urbanization, and industrialization (as in the Western countries and in Japan), the size of family is reduced by birth control and the birth rate falls, eventually reducing the rate of population growth.

The theory of the demographic transition gave a plausible interpretation of demographic events in Western countries up to World War II. Demographers sought to extrapolate it in time, by projecting the then existing trends, and in space, by assuming that in the process of modernization the rest of the world would follow the same sequence of events as in the West. Population “projections” based on extrapolation of natality and mortality trends gained wide currency and were commonly regarded as estimates rather than as the mechanical extrapolations that they really were.

It is ironic that demographers developed the techniques for projecting certain long-standing trends in the components of population growth, especially in natality, just at a time when these trends were about to dissolve. New attitudes favoring earlier marriage and more children appeared in the very societies where the great majority of families had been practicing birth control. The recovery of the birth rate in Western countries just before, during, and especially after World War II violated the projections of previous trends and those formulations of the demographic transition that considered Western countries to be approaching a stationary or declining population. While the prolonged “baby boom” after World War II has receded, all Western countries continue to have modest rates of population growth.

The demographic transition has not fully materialized in non-Western cultures, aside from Japan. The transition has largely run its course in countries inhabited by peoples of predominantly European race and heritage, including Europe, the Soviet Union, and the overseas countries of chiefly European background. As yet, very few non-European countries have clearly reached the stage of declining birth rates and slower rates of population growth. There has not been a continuum of countries moving through the stages of transition, as Western countries were doing at the time when the theory was developed. Instead, there is now a sharp division between countries that have passed through the “vital revolution” and now have modest birth rates and growth rates, and countries in which the death rates, but not the birth rates, have been going down, so that the rate of population growth has been accelerating. This division separates the developed from the underdeveloped world, and, aside from the important exception of Japan, it also separates the peoples of European race and tradition from the peoples of the rest of the world. But there are clear indications that other nonEuropean countries such as Taiwan and Korea may now be entering the later phases of transition, and the development of government policies and especially of better contraceptives may well accelerate the transition. As yet, no country has become “modern”—in the sense of achieving mature socioeconomic development—without also undergoing a decline in its birth rate.

Later methodological developments

Two major developments have occurred in demography since World War ii as a result of the problems and failures of previous population projections: the development of a complex methodology to analyze trends in natality and the use of field surveys to determine causal factors affecting the number and timing of births.

The attempts to obtain better forecasts of future population resulted in successive improvements in the measuring of reproduction. These included the refinement of the crude birth rate to a population standardized by age; Lotka’s historic breakthrough in determining the true birth and death rates, given the continuation of existing age-specific natality and mortality rates; the analysis of births by duration of marriage, developed primarily in Europe (since such data were not available in the United States); the analysis of cohort fertility, that is, the number, spacing, and order of births per woman in her total reproductive experience (Whelpton et al. 1965); and stable population analysis, that is, the analysis of mathematical regularities in the interrelations of births, deaths, age structure, and population growth at fixed schedules of natality and mortality (Coale & Demeny 1966). Some of the methods in this area of growing demographic importance involve elaborate computations that are being facilitated by advances in computer technology.

Despite great technical virtuosity and much better understanding of the various ways in which natality may be measured, it is too early to tell whether these efforts have added much to the accuracy of population forecasts, although they have improved understanding of current natality trends. Cohort fertility analysis certainly provides meaningful interpretations of past trends and provides the basis for reasonable estimates of the total number of children a cohort of women will bear well before they have actually reached the end of their reproductive period. In the United States women born during the period 1905–1914 show the smallest average number of births and stand at the end of the long fertility decline that began in the early nineteenth century. It seems certain that later cohorts of women–that is, those born during the period 1915–1935–will show a larger average number of births (U.S. Department of Health…1966, p. 6).

After World War n, couples in the United States married earlier, had their children earlier, and had more children than their parents. The result was the higher birth rate in the United States and in some other Western countries during the postwar period. Recent trends suggest that these forces are receding.

The official statistics used in the sophisticated methods of analysis referred to above have not given the reasons for the changes that have occurred. These have been sought in the second of the recent major developments in demographic methodology: field studies of attitudes, motivations, and expectations relating to family size. In the United States demographers have conducted a series of national sample surveys of attitudes and practices in relation to family planning. These surveys are documenting the changing aspirations of American families with regard to the size of family desired and the changing practices of marriage, spacing of children, and methods of family limitation (for example, see Whelpton et al. 1965; Westoff et al. 1961; 1963).

Demography and the population explosion

Since World War n, interest in population problems has re-emerged with great force. This is related to the rapid progress achieved in controlling or postponing deaths throughout the world, which has occurred without a compensating decline in the birth rate in the underdeveloped areas. The result has been the acceleration of population growth, dramatized in a vast and sometimes controversial literature about the “population explosion.” The rate of world population growth, over 2 per cent per year, is accelerating [seePopulation, article onPopulation Growth].

World population growth in the present period is historically unique, and there is a general realization that it leads to serious obstacles to the whole range of socioeconomic development, whether in food, health, education, housing, or the general level of living. Population growth is a major block to the satisfaction of rising aspirations in the underdeveloped countries (Coale & Hoover 1958).

In both developed and developing countries the rapid growth of metropolitan areas with their wide range of problems has also been classified as a “population problem” on the mistaken assumption that this is primarily due to the birth rate rather than to migration, which has been the principal factor. It is recognized that population growth and concentration have contributed to a wide range of problems involving the quality of education, the urban sprawl, the contamination of the atmosphere, and, according to some, the mediocrity of mass culture and the cacophony of much of modern life.

As logical results of these concerns, social scientists have become more interested in the population problem, whether defined as a social problem or as an area of scientific interest. Demography has, of course, provided analysis of the population trends and prospects that underlie this concern. Prior to World War Ii demographic studies were largely confined to countries with adequate censuses and vital statistics–that is, chiefly countries of the Western world. In recent years there has been growing interest in the demography of the underdeveloped world, where great ingenuity and methodological skill are often needed to make up for the absence of reliable data. This changing emphasis has been reflected, for example, in the much greater attention given the underdeveloped areas in the Second World Population Conference in Belgrade in 1965, as compared with the First World Population Conference in Rome in 1954 (World Population Conference 1966, p. 2).

The growth of applied demography

Demography has supplied much of the factual background for the population policies and family planning programs that have been adopted by several of the developing countries. Much of the demographic literature now relates to attitude studies and to action experiments designed to introduce family planning in these areas.

On the world scale, the field surveys of knowledge, attitudes, and practices (KAP studies) concerning family size and family planning are perhaps the broadest cross-cultural series of studies on any subject in the social sciences. Sample surveys of this type have been done in some twenty countries in Africa, Asia, and Latin America. These surveys have revealed the feasibility of obtaining useful information on such delicate subjects in all societies; the existence of a substantial “market” for contraceptive information and services almost everywhere; and actual contraceptive practice in close relation to the degree of modernization of the country or socioeconomic class concerned [seeFertility Control].

Although demography has been described as “observational,” as opposed to experimental, at least some demographers have embarked on controlled experiments in relation to efforts to reduce birth rates. In several instances, the Kap studies have included an action component, that is, experimentation in introducing family planning to the population concerned. These studies have met with varying success, depending on the characteristics of the populations and the methods of education and motivation employed. Such attempts have been successful where the population was already in the stream of modernization, had experienced increasing survival of infants, and had achieved some success in avoiding births through postponement of marriage and through contraception and abortion. Projects of this nature have been working in Taiwan, Korea, and Ceylon. However, where the population had not already made serious efforts to reduce family size, as in India and Pakistan, the results of such experiments have been limited (Conference . . . 1962; International Conference… 1966; Studies in Family Planning).

A number of countries have adopted national programs for introducing family planning: Communist China, South Korea, Taiwan, Malaysia, Singapore, Ceylon, Pakistan, Turkey, the United Arab Republic, Tunisia, Morocco, Barbados, Jamaica, Honduras, and Chile. The list grows each year. Most of these programs are as yet too new and too small-scale to have achieved measurable success in reducing the birth rate. However, their chances for success may change rapidly with the improvement of contraceptive technology, notably oral contraceptives and plastic intrauterine devices. All contraception involves motivation; the newer methods are effective because they help the less strongly motivated and those living in circumstances where earlier methods were impractical. It seems likely that these and further improvements will revolutionize the whole approach to family planning in developing and developed countries alike (International Conference ... 1966).

There is controversy among demographers about the scientific relevance of applied studies in their field. There is less controversy about the role of getting better information on vital statistics and population growth, since these pursuits serve both academic and applied ends. In over half the world, including most of the countries that have adopted population policies, official vital statistics are inadequate for determining either the true levels or year-to-year changes in birth rates, death rates, and population growth. New approaches that are being undertaken to obtain better estimates include closely supervised registration in sample areas, repetitive surveys, and various combinations that have come to be called “population growth estimation studies.” The real measure of the success of a national family planning program is reduction in the birth rate and in the rate of population growth, and demographers are therefore becoming increasingly involved in problems of measuring population growth, as well as in the evaluation of the results of family planning programs.

Demography in the social sciences

Demography is generally considered an interdisciplinary subject with strong roots in sociology and weaker, but still important, connections with economics, statistics, geography, human ecology, biology, medicine, and human genetics. It is rarely thought of as a completely separate discipline, but rather as an interstitial subject or as a subdivision of one of the major fields. In English-speaking countries persons who describe themselves professionally as “demographers” usually hold positions of broader definition as sociologists, economists, or statisticians, or are in offices and research organizations whose titles include the word “population” but only rarely “demography,” a word that is more commonly used in other countries.

Interest in demography has led recently to the rapid multiplication of offices and institutes devoted specifically to population research. In the United States there are some ten such institutes associated with universities. There are important centers of demographic study in France, Italy, the United Kingdom, Australia, and Japan. The United Nations sponsors three regional centers of demographic training (in Santiago, Chile, for Latin America; in Bombay, India, for Asia; and in Cairo, United Arab Republic, for north Africa), and others are under consideration. Some of the most rapid progress in demographic work is occurring at newly established centers in eastern Europe and in the developing areas.

Demography is, in one sense, a general servant of other social sciences. It evaluates and initially digests the vast reservoirs of social data compiled in censuses and vital statistics. It provides substantial raw material for the study of social, political, and economic change. Moreover, in spite of past disappointments over their accuracy, projections and estimates are continually requested from demographers for a multitude of planning purposes.

Demography has not had a prominent place in social scientific theory except in that of economics, through the works of Mai thus. It is quantitative, empirical, and methodologically rigorous. Its subject matter is statistical categories that only indirectly reflect real social groups. Its quantitative documentation of specific social change is not readily integrated into the structural-functional theories prevailing in sociology, which are commonly speculative and hard to subject to empirical tests.

Within its own domain demography has had its greatest successes in the analysis of mortality [seeLife tables; Mortality]. Its greatest interest and virtuosity has been in the study of natality [seeFertility] . The stepchild of demography is migration, which up to now has defied the application of refined measurements comparable to those developed in the other two fields. Although international migration is no longer of great demographic importance, internal migration in the United States, for example, is the chief cause of variations in rates of population growth between states, cities, and regions. The importance of migration, as well as the advantages of the new computer technology, may bring greater talent and resources into this field [seeMigration].

In recent years perhaps the most neglected area in demography has been on the important frontiers between demography and economics, in such areas as population growth in relation to capital formation; application of life table principles to labor force changes; the economics of health, morbidity, and mortality; and the economic implications of different levels of morbidity and mortality. There are also unexplored possibilities for more fruitful cross-disciplinary work between demography and the fields of anthropology, politics, geography, ecology, and genetics [see Genetics, article ondemography and population genetics]. There are beginnings, but as yet the joint efforts in these related fields are minimal.

Coale, Ansley J.; and Hoover, Edgar M. 1958 Population Growth and Economic Development in Lowincome Countries: A Case Study of India’s Prospects. Princeton Univ. Press. → The most comprehensive work on this subject.

Conference On Research In Family Planning, New York, 1960 1962 Research in Family Planning: Papers. Edited by Clyde V. Kiser. Princeton Univ. Press.

Demographic Yearbook. → Issued annually by the United Nations since 1948. The standard international compendium and source book for world demographic information. See especially the 1948 issue. Demography. → Published irregularly since 1964 by the Population Association of America.

Great Britain, Royal Commission On Population 1949–1954 Papers. 6 vols. in 7. London: H.M. Stationery Office.

Hauser, Philip M.; and Duncan, Otis Dudley (editors) (1959) 1964 The Study of Population: An Inventory and Appraisal. Univ. of Chicago Press. → A major compendium of scholarly papers on the history, substance, and status of demography.

International Conference On Family Planning Programs, Geneva, 1965 1966 Family Planning and Population Programs: A Review of World Developments. Edited by Bernard Berelson et al. Univ. of Chicago Press.

Lorimer, Frank 1957 General Survey. Part 1, pages 11–57 in David V. Glass (editor), The University Teaching of Social Sciences: Demography. Paris: Unesco.

Lorimer, Frank (1959) 1964 The Development of Demography. Pages 124–179 in Philip M. Hauser and Otis Dudley Duncan (editors), The Study of Population: An Inventory and Appraisal. Univ. of Chicago Press.

Lotka, Alfred J. (1925)1957 Elements of Mathematical Biology. New York: Dover. → First published as Elements of Physical Biology.

On Population: Three Essays, by Thomas R. Malthus, Julian Huxley, and Frederick Osborn. New York: Mentor, 1960. → A paperback publication. Contains “A Summary View of the Principle of Population” by Malthus, first published in 1830; “World Population” by Huxley, first published in 1956; and “Population: An International Dilemma” by Osborn, first published in 1958.

Pearl, Raymond; and Reed, L. J. 1920 On the Rate of Growth of the Population of the United States Since 1790 and Its Mathematical Representation. National Academy of Sciences, Proceedings 6:275–288.

Petersen, William (1961) 1964 Population. New York: Macmillan. → An introductory textbook. Population. → Published since 1946 by the Presses Universitaires de France for the Institut National d’Etudes Demographiques.

Population Bulletin of the United Nations 1963 No. 7.→ Discusses conditions and trends of fertility.

Population Index. → An annotated listing of current publications. Published since 1935 by Princeton University, Office of Population Research, and the Population Association of America, Inc.

Population Studies. → Published since 1947. Issued by the London School of Economics and Political Science, Population Investigation Committee.

United Nations, Department of Social Affairs, Population Division 1953 The Determinants and Consequences of Population Trends.Population Studies, No. 17. New York: United Nations.

U.S. Department of Health, Education and Welfare, Public Health Service 1966 Natality Statistics Analysis, United States, 1963. National Center for Health Statistics, Series 21, No. 8. Washington: Government Printing Office.

U.S. National Resources Committee, Science Committee 1938 The Problems of a Changing Population. Report of the Committee on Population Problems. Washington: Government Printing Office.

Westoff, Charles F.; Potter, Robert G.; and Sagi, Philip C. 1963 The Third Child: A Study in the Prediction of Fertility. Princeton Univ. Press.

In this discussion we will leave aside such subjects as population genetics, eugenics, and the geographical distribution of people in a particular area. We will concentrate instead upon those theories which relate population size to environment. This relationship is expressed, for instance, by the terms “overpopulation” and “underpopulation” and by the concept of an optimum state which lies in between.

It is appropriate to start with a short historical overview.

Antiquity. Since overpopulation in China goes back to very ancient times, it is not surprising that Chinese philosophers, especially Confucius, entertained the notion of a numerical balance between population and environment. They also looked for means to check the increase in numbers. The foundations of a theory of optimum population level, fully stated only in the twentieth century, can be found in their writings.

In ancient Greece, the earliest thinkers favored the expansion of population. Plato, however, became the foremost exponent of the restrictionist point of view, although he was by no means its first representative. In his Laws, following Hippodamos, he advocated an absolute limit to the number of citizens and suggested means to that end which would frighten today’s moralists. In Plato’s Laws, however, as well as in his Republic and in Aristotle’s Politics, the perspective is rather narrow, and any concern for the whole of mankind is wellnigh missing. Fear of overpopulation finally contributed to the decay of Hellenic civilization. At this point, Polybius analyzed the causes of the low fertility of the Greek population and proposed remedies—but it was too late.

Early Rome was characterized by a fertility cult, as was typical of many rising civilizations, including Greece. This ideal found practical support in military and political expansion. From Ennius to Varro, all the writers of the republican period claimed that the primary function of marriage was to provide citizens—if not soldiers–for the state.

Later writers denounced the evils of depopulation, and several emperors, notably Augustus, introduced legislation to encourage parenthood. In spite of these efforts, Rome’s lack of men finally contributed to its downfall, since it was unable to hold back the barbarian invasions.

The Middle Ages. Medieval population theory was not, generally speaking, grounded in economics. Since the concepts of state, race, and nation made little sense to medieval man, political concern for population growth could not crystallize. Gradually, however, the depopulation ensuing from disastrous invasions gave rise to the feeling that population growth in itself was a good thing and a mark of divine favor. This view was to survive a long time, and to this day it has not completely vanished.

The setting up of a social hierarchy could only strengthen this line of reasoning. The leisure classes dreaded any decrease in the numbers of those whose labor they were exploiting (the analogy with a herd was becoming obvious). Thus, the return of the populationist tradition coincided with the reorganization of Western society after the era of feudalism.

The Enlightenment. The populationist theory which appeared during the seventeenth century and flourished in the eighteenth century rested on paternalistic premises. According to an early statement by Guillaume Bude: “The king’s glory is in the multitude of the people.” Similarly, Perriere asked: “Who will carry the weapons, if men are lacking?” Jean Bodin was even more explicit: “There is no wealth nor strength but in men.”

Mercantilism was a natural extension of populationist theory from the political to the economic field. Mercantilist theory was nationalistic and expansionist in outlook; it aimed at increasing both employment and number of men by processing as much raw material as possible within the national boundaries. In fact, it was less of a scientific theory of population than a political attitude. Political concern with increasing the population as a means of promoting wealth and power for the lord, the king, and later for the state, extended through the centuries, well beyond the period of mercantilism. Most orthodox thinkers in the eighteenth century instinctively took a populationist position. The frankest statement of that position was given by Turmeau de la Morandiere, in one brutal sentence: “Subjects and beasts must be multiplied.” We shall see why nationalism, in its early stages, and dictatorships are more prone to populationist arguments than are democratic regimes. In Germany, Hermann Conring also attributed the power of states mainly to population. In England, at the same period, another confirmed populationist was William Petty, who founded the science of “political arithmetic,” or demography, and who used his truly brilliant gifts to raise questions so novel that they opened up vast areas to scientific investigation.

In France, the physiocrats and their leader, Frangois Quesnay, thought that proper regulation of landed property by means of capital investment should take precedence over population increase. Quesnay’s Tableau economique (written in 1758 and revised in 1766) contained the first dynamic model of a national economy and was in this respect a forerunner of modern national accounting and the matrix developed by Leontief [seeInput-output analysis].

Adam Smith took little interest in the population question, which, as a matter of fact, baffled him slightly. The first to raise it in a formal way was Thomas Malthus.

Malthus and his contemporaries. The autocratic ruler who wields absolute power without avowed obligations always desires a greater number of subjects. The scope of this observation extends beyond the field of demography; it applies to the sovereign as much as to the collector of objets d’art, to the head of a family as much as to the office manager. But when his subjects—or rather, the objects in his possession—have rights or occasion some expense, the ruler’s point of view changes, and he grows increasingly cautious with regard to numbers. Such a situation existed in seventeenth-century England, where the poor laws resulted in an increasing burden for the ruling class at the same time that the poor themselves were ceasing to rely on charity and were becoming conscious of their rights. This new dispensation was the cue for Malthus.

The desire of Malthus and his supporters to see poor families restrict their progeny has been described alternatively as altruistic and egoistic. Indeed, it is both things at the same time: pity for the paupers and dread of having to share with them.

Many members of the ruling classes, including a majority of classical economists, agreed with Malthus that it was advisable to keep down the size of the labor force. Reacting to Malthus and his school, the contemporary socialist writers took an opposite stand: Owen, Fourier, Proudhon, and Marx were all unwilling to ascribe pauperism to excessive population and therefore rejected the remedies advocated by Malthus. The egoism demonstrated by Malthus, particularly in his famous statement that a man born into a world already owned by others has no inherent right to a place at nature’s feast, elicited violent indignation. This reaction is still partly responsible for several of the misconceptions that surround the population problem. Let us try, then, to clear up these misunderstandings by presenting the problem in the light of the most recent scientific developments, while not forgetting that one’s point of view on the subject may vary with one’s social status.

The concept of optimum population

The concept of optimum population corresponds to the idea of a happy medium: it is assumed that since we talk about overpopulation and under-population, there must be some intermediate stage that avoids either defect. We have already seen that this notion of the proper limit, this concern about avoiding both overpopulation and underpopulation, has a lengthy history. Plato aside, it can be found in rudimentary form in the works of many authors in various countries, from Giovanni Botero to Voltaire to the classic liberal economists. However, it was first stated in scientific terms only at the beginning of the twentieth century, when the word optimum was applied to population by the German economist Julius Wolf. He was soon followed by other economists, such as Knut Wicksell (Sweden), Paul Mombert (Germany), and Edwin Cannan (England). The notion of optimum population was further elaborated during the interwar period by A. B. Wolfe and H. P. Fairchild in the United States and by Lionel Robbins and A. M. Carr-Saunders in England, among others. Meanwhile, it was criticized mostly by writers on the Continent, such as Corrado Gini, Eugène Duprèel, W. E. Rappard, and Adolphe Landry.

Determining optimum population

Talking of an “optimum population” implies trying to find out how many inhabitants it would be desirable to have if a given end is to be achieved. The end itself remains to be specified, and there are a number of such ends that can be proposed. Among them are the following:

Full employment, that is, work for all persons of working age;

Power, that is, the full range of means that can be set to work to obtain a collective end, whatever the end may be;

Long life and good health;

Knowledge and culture;

Aggregate welfare, or, put in a slightly different way, the aggregate income of the population;

Still other objectives, such as social harmony, family stability, and so on, may be conceived; thus Plato had a political view of optimum population and Eugene Dupreel an aesthetic one. Here we shall only discuss two of these objectives: the economic objective, that is, the average standard of living, and the objective of the collectivity, which is much the same thing as power. The pursuit of either of these objectives leads to a specific optimum population size.

Minimum and maximum population

Before proposing a definition of optimum population, we have to specify the extremes on either side of the

optimum. In other words, we have to specify the range between minimum and maximum population.

Minimum population is determined jointly by economic and biological considerations. Life is very hard to sustain without at least some division of labor. Besides, a minimum number of people is required in order to provide marital partners for all, without too much consanguinity or disparity of ages. On these grounds, it has been estimated that an isolated population cannot safely fall under five hundred or six hundred inhabitants [seeGenetics, article onDemography and Population Genetics].

Maximum population is the highest that could conceivably subsist on the total product, provided it is distributed fairly among all.

In both minimum and maximum, the population is drawn toward the bare subsistence level—a very low standard of living indeed.

In Figure 1, the horizontal axis measures population size, and the vertical axis measures production per head. The minimum population is equal to p, and the maximum population to T. The subsistence level is ST or mp. Between these two extreme positions, there must be at least one population size that maximizes the standard of living. This is the optimum population, P, with a standard of living equal to MP.

The general model

In order to specify the position of the optimum population, P, we cannot avoid using a very simplified model. We shall review its defects at a later point.

In Figure 2, population size is still measured on the horizontal axis. Curve AA’ denotes marginal productivity, that is, the increase in total production resulting from the addition, one by one, of extra individuals to the population. Initially this curve rises, thanks to the division of labor and the sharing of overhead costs; the latter part of the curve slopes downward, reflecting saturation and diminishing returns. The curve’s highest value (J) is reached at population size K. Curve BB’ represents total production; it is the integral of curve AA’. Its point of inflection, /, is for population size K, the same population size that maximizes curve AA’.

Point M is touched by a tangent from O, the origin. Production per capita (measured by the tangent of angle MOP) is highest for that point M; On the right of M, it decreases. Curve mRS also indicates output per capita, but this time as measured on the vertical axis. It is maximized at population size P, corresponding to curve Bbf. Curves Aa’ and mRs cross at R, since marginal productivity and output per capita are equal at that point. On the production axis, OV, rap, or ST represents subsistence level.

The way in which optimum population is derived can now be described as follows:

If n is population and f(n) is total production, then curve AA’ represents f’(n), curve BB’ represents f(n), and curve mRs represents f(n)/n. The economically optimum population, n0, is given by f’(n0) = f(no)/n(0). Furthermore, V being the subsistence level, both nm (the minimum population) and nM (the maximum population) are given by f(nm)/nm= f(nM)/nM = V. A second kind of optimum population, nv, is that which maximizes power, in a sense to be described below. This optimum population occurs where curve AA’ intersects the horizontal at V, f’(np) = V.

Now we have at our disposal all the elements required to assess the state of a population that is

subject to environmental pressure. Going from left to right in Figure 2—that is, in the direction of population growth—we find:

p = minimum population,

K = population with highest increase in production as a function of population size,

p = optimum population from an economic point of view,

Q = optimum population insofar as power is concerned (see below),

T = maximum population.

Optimum power

When we speak of optimum power, we have in mind not only military power but also any objective involving the collectivity. Such an objective can even be the wealth of a despotic ruler or sovereign who aims at the highest possible income by exploiting the population.

If we ignore the case of minimum population, which has no practical importance here, we see that power, defined in these terms, is whatever exceeds the subsistence level. Power can therefore be described as the area in Figure 2 between curve AA’ and straight line VS. Maximum power, N, is attained for a population size Q. Beyond population size Q, power decreases, for when marginal productivity is less than average production, any additional person can be fed only at the expense of the surplus.

Since point Q is on the right of P, the population that is optimum for maximizing collective power is always larger than the population that is optimum from the economic point of view. This difference has important social and political implications. It explains why, all other things being equal, totalitarian states have more of a stake in acquiring large populations than have democracies, which tend to be more concerned with the standard of living. Thus it will easily be seen that in any sociopolitical system the effect of any military or other collective burden is to raise the size of a country’s optimum population. Let us refer, at this point, to Figure 3, in which the upper total production curve is identical with curve BB’ in Figure 2, with the maximum at M, when P is optimum population size.

The lower curve in Figure 3 is the result of a constant shift on the vertical axis, so that the tangent through O, the origin, now passes through point M′. On the horizontal axis, M′ corresponds to P′, which is well to the right of P. The way in which collective burdens increase optimum population can also be demonstrated as follows: Let np (the P of Figure 2) be the optimum population

size when there is no collective burden. Production per capita is f(n)/n, which is maximized (differentiate) when nf’(n) – f(n) = 0. Thus, as was noted for Figure 2, npf’(np) – f(np) = 0.

Now if a collective burden, K, is added, usable production per capita is reduced to [f(n) – K]/n. This function will be maximized when nf’(n) –f(n) +K = 0, or

The only way to achieve this equality is for n to be larger than np, since f’(n) is a decreasing function of n in the region in question.

The influence of fixed costs. The important conclusion reached in the preceding section can now be generalized: a country that, for any reason, has to meet fixed costs or, at the very least, costs that are disproportionate to the size of its population will benefit if it succeeds in increasing its population. For instance, if the aged members of a population are to be helped by retirement pensions or other means, the economically active members of that population will benefit from an increase in numbers, so as to spread the burden over a larger number of shoulders. In such a case, optimum population size is increased because of two factors: the number of retired persons, since these are economically inactive, and the number of economically active persons, for reasons already explained. From this we can judge what kinds of problems arise when, for instance, the retirement age is lowered: not only do many of the economically active cease contributing to production by becoming economically inactive, but a need also arises for an increase in the economically active population. Let us spell out the same point in figures. Suppose that a population of ten million happens to be of economically optimum size. If one million of its economically active members suddenly become economically inactive, the standard of living is going to drop. In order to raise the standard of living to the highest level possible for that population, it would be necessary to attract a number of immigrants in excess of one million—two or three million, for example.

Evolution of optimum population

Optimum population has increased considerably since the 1860s in the developed countries. In every case, the increase in optimum population has been faster than the increase in actual population. This trend has resulted from (a) the importance of fixed costs in modern society; (b) the fact that industrial production is less subject to decreasing returns than is agricultural production; (c) the fact that technological progress, contrary to what is generally thought, does increase the number of jobs.

Under an agrarian economy, the populations of European countries traditionally exceeded the optimum. This was demonstrated when, as usually happened, the standard of living improved after the population had been reduced by a severe epidemic, such as the Black Death in the fourteenth century.

Today’s situation is entirely different. Let us consider the example of Switzerland. In the late eighteenth century the population probably did not exceed 1.7 million inhabitants. Nevertheless, some of them were forced to emigrate, and Swiss men often served in foreign armies. We can assume that the optimum size of the Swiss population at that time was somewhere between one million and 1.5 million people. Today the population is over five million, which must still be below the economic optimum, since it has been necessary to call on 700,000 workers from abroad.

The reversal of the secular trend in migration, which instead of flowing out of Europe, as it did for so long, is now flowing in Europe’s direction, also shows how much the optimum population must have grown in the course of the twentieth century [seeMigration].

Review of the optimum population concept

Early in this century, when the concept of optimum population was given systematic expression, writers on the subject thought that a definitive solution had been found for the population problem, at least in theory, and that the only difficulty remaining was to apply the solution in practice. This opinion did not survive long under scrutiny, especially since the facts were against it. The concept of optimum population is indeed too static; it implies that population size can vary without any change occurring in the other factors that could affect the population’s standard of living.

Besides, even if it were possible, at a given point in time, to calculate a country’s optimum population correctly, it would still be difficult to base a population policy on that calculation. For example, if it could be demonstrated that 400 million inhabitants would fare better in present-day India than the actual 500 million, there could be no question of killing 100 million people in order to improve the others’ lot. Conversely, if it could be shown that the optimum population of France is 60 million instead of its present 47 million, or that that of Australia is 30 million instead of its present 11 million, there could be no question of suddenly raising the population of these two countries by such large numbers. Even if enough immigrants could be found, there would still be the problems of fitting them all out and providing them with housing, schools, and so on. Thus, there is also a question of time involved.

Considerations such as these lead to a less static orientation or, in other words, to the study of population dynamics. But before we turn to that subject, it should be stressed that the concept of optimum population is a usable one provided one is discussing, as we were above, the way in which a specific factor affects the optimum. It is, therefore, a useful tool, and one that, if used correctly, would enable us to explain many historical phenomena and in future to avoid certain dangerous sociological misconceptions.

Optimum population growth

Technological progress and employment

The problems of development, and therefore the very concept of an optimum rhythm of population growth, hinge on a very important phenomenon which has been too often neglected by economists because the subject breeds superficial prejudice and discourages empirical research. That important phenomenon is the relationship between technological progress and employment.

It is commonly believed that technological progress has the effect of reducing employment. Although this opinion, which is very old, has been constantly contradicted by the facts, it nevertheless continues to command belief and regains strength with every technological innovation, as it has with automation. If this opinion were based on fact, if the economy really were headed toward the “pushbutton” economy imagined by Simonde de Sismondi (the king of England, alone on his island, enjoying a very high standard of living through the operation of handles and levers), then population growth would become useless. Furthermore, the economic system would have to be altered drastically. But actual trends have been in the opposite direction. The gainfully employed population is very much larger now in the developed countries than before the industrial revolution, while it is in the underdeveloped countries—that is, in the countries that lack machines—that underemployment is most severe.

This is not the place to expound a theory of employment and technological progress. Let us content ourselves with emphasizing the fundamental roles of population growth and of the proliferation of consumer needs. The orientation of consumption toward goods that contain an ever-increasing proportion of value added by manufacture and by services continually raises the number of jobs and at the same time reduces the threat of overpopulation. Of course, other factors may prevent full employment in a specific country. It is even conceivable that there will be a constant increase in the number of available jobs and yet that full employment will never be reached.

We are now in a position to approach the question of an optimum rate of population growth.

The concept of optimum growth rate

When a population grows very rapidly, it is confronted with a major need for new capital goods. It is therefore compelled to devote a large part of the national income to capital investment, and, as a result, to lower its standard of living. If, on the contrary, the population decreases or remains constant, it suffers various troubles that are difficult to analyze but that have results which are quite obvious. Not one single historical or present-day instance can be cited of a declining or stagnating population that has enjoyed or is now enjoying any real economic expansion.

If we follow a chain of reasoning analogous to the one that led to the concept of optimum population size, we come to the conclusion that there must exist, between the two extremes of rapid growth and decline or stagnation, some intermediate condition of the population that guarantees the highest possible rate of growth in the standard of living. Let us call such a condition the optimum rate of growth, as opposed to the static optimum, defined above, of population size.

The concept of optimum rate will become clearer if we examine first the costs, and second the advantages, of growth. As previously, we are concerned only with the economic aspects.

The cost of growth

Once again, we shall simplify the problem by turning to a model. If, as a result of certain investments, I, national income increases in each of the years following the investments by a quantity r, the ratio r/l is the national rate of interest, T. The reciprocal, I/r, is called the capital-output ratio. For instance, if an investment of 1,000 million increases national income by 300 million a year, the national rate of interest of that investment is 30 per cent. More often than not, the national rate of interest is between 20 and 50 per cent.

Let us accept the simplifying assumption that, for all the investments made each year, the capital-output ratio remains constant, so that the increase in national income is equal to IT. If the ratio I/r remains constant every year, national income will grow exponentially at a rate (It)/r. And if population itself remains constant, the increase in per capita national income, or in average standard of living, will follow the same geometrical progression.

Let us now introduce population increase into the model. By demographic investment we mean all outlays or efforts aimed at avoiding a deterioration of living standards as a result of growth. Many authors have used the same capital-output ratio for population increase as for the growth of national income that results from economic investments. For example, if 4 per cent of the national income has to be invested in order to raise national income by 1 per cent in each of the years following the investment, these authors assume that 4 per cent of the national income would also be required in order to accommodate a population growth rate of 1 per cent without a decline in income per capita. This equation of one type of return on investment with another is a mere statistical convenience that may sometimes be very remote from fact. Except when the rates coincide by chance, the assumption is justified only in instances where all persons added to the population are completely unproductive, i.e., contribute nothing to national income.

Some idea of the size of the required demographic investment can be obtained by adding to the cost of the technical means of production the cost of educating a man to the level at which he can make use of them—a process that may add up to 10 or 12 years of work. Consequently, a 1 per cent increase in a population would, if we assume that this population is stable, absorb 10 or 12 per cent of its national income. This figure is much higher than the one quoted previously for the capital-output ratio. It would be only too easy to infer from this that any growth of population is costly in itself and that, from a strictly economic point of view, it is in a population’s interest not to grow, and even to decrease. But this conclusion runs counter to too many empirical findings not to be highly suspect. Moreover, the advantages of population growth should be taken into consideration, and a clear distinction made between advantages of a purely economic nature and the social advantages that have an effect on the economy.

Economic advantages of growth

We have already mentioned overhead, or fixed costs, and the fact that in an industrial economy the classic law of diminishing returns is superseded by a more favorable law and sometimes even by a marked increase in returns.

Another factor, which has been neglected but which should certainly be mentioned, is the way in which growth facilitates the correction of every mistake, every structural defect or imbalance, in any aspect of population distribution—geographical, occupational, or other. When a faulty proportion, of whatever kind, has to be corrected in any organism whatsoever, this can be done by amputation—that is, by taking something away. But in social matters it is hard to take anything away from what already exists, and strong opposition is likely to be encountered. Population growth, however, makes it possible to improve existing structures without encountering these problems, since faulty proportions can now be corrected by adding what is needed instead of taking away what is not needed.

The advantages of growth are still more striking in cases where the proportions that need to be corrected are continually changing. This is especially true of technological progress and economic progress, both of which are continually modifying the occupational distribution of the labor force, not only among the three traditional sectors—primary, secondary, and tertiary—but also among the occupational subdivisions of each sector. In a stationary population with low mortality, the economically active population is replenished by the younger age groups at a rate of only 2.2 per cent a year. Such a rate is not sufficient to ensure the occupational reallocation required by technological change. The result, relatively speaking, is an excess of people in obsolete trades and a consequent slowing down of economic progress.

Social advantages of growth

The first advantage of a growing population that should be mentioned here is its age distribution. Since mortality has declined in most human populations and since, as a result, the absolute number of the aged is bound to increase for years to come, a population that remains about the same size is bound to contain fewer young people and fewer adults of working age. In other words, the average age of the population is going to increase rapidly. When a population ages in this way, there are certain material consequences that have been fairly well investigated and certain moral consequences that so far have hardly been studied. However, it is generally acknowledged that the spirit of enterprise does not flourish in an aging population; nineteenth-century France, and perhaps modern Ireland, are significant instances of this. Nor is an aging electorate the only factor. Not many new businesses are created when the generations hardly replace one another, since the younger generation is content to wait until jobs are vacated by the older. In such a population most positions of power and responsibility are held by elderly people, and thus institutional rigidities set in. It seems that there is a certain analogy in this respect between social and biological organisms.

The large proportion of one-child families in a stationary population is another reason why the spirit of enterprise is weakened in both the older and the younger generations.

Estimating the optimum growth rate

As far as research on a specific country is concerned, the optimum growth rate has been just as neglected as the optimum population size. There is, of course, no question of proposing a single rate for all economies. In an agrarian economy with an arrested technology, growth is advisable only if the country is underpopulated. Even then the optimum growth rate will be slow, unless underpopulation is very marked, as was the case in the United States and Canada during the eighteenth and nineteenth centuries.

Thus the concept of optimum growth rate is better suited to an industrial economy. Generally, the more abundant or accessible natural resources are through international trade, and the faster technological progress, the higher the rate of population growth should also be. For western Europe during recent years, a growth rate of between 0.5 and 1 per cent per year seems to have been necessary and by no means excessive.

The problems of measurement in this area stem from the fact that it is harder to measure the advantages of population growth—advantages that, as we have seen, are in part social—than the disadvantages. Even if all the elements involved were known, it would still be necessary to choose between maintaining current standards of living and making sacrifices for the sake of future generations. Finally, it should be remembered that demographic trends are slow and far-reaching, so that the consequences of any change that is too sudden may be felt for years afterwards.

Social and political aspects of growth

Although it is now possible to outline a theory of the influence of population growth on economic development and standards of living, various elements needed to apply it correctly are still missing. This uncertainty has only exacerbated political and class conflict over population policies. Marxist doctrine, for instance, has never recognized the possibility of a population problem, especially one of overpopulation. This position is out of date; it still shows the effects of the violent reaction against Malthus’ egoistic view of society. However, there have been significant departures from this position in such countries as Poland and Yugoslavia, where the birth rate—and thus the growth rate—has been voluntarily reduced in order to make it possible to meet the cost of demographic investments. In Western countries, many Marxists take a more realistic view of population growth than is warranted by orthodox Marxist doctrine.

In capitalist countries there is still some fear of the effects of population growth on employment, although recent trends in Germany, Austria, Switzerland, the Netherlands, Italy, and other countries have demonstrated the weakness of economic theory on this subject. Meanwhile, these same countries dread population increase in the underdeveloped countries of the Third World—an attitude that is reminiscent of Malthus but that, since 1962, is no longer opposed by the Soviet Union.

The underdeveloped nations themselves are influenced by two conflicting trends. Tradition, concern for power or prestige, and sometimes the availability of wide-open spaces lead to a favorable view of present rapid growth rates. This attitude is exemplified by the countries of Latin America and tropical Africa. On the other hand, concern about standards of living and fear of overheavy demographic investments are arguments in favor of—or at least not against—the acceptance of birth control. This attitude is encountered mostly in the Far East and the Arab world.

All too often in the history of ideas authors have believed themselves to have given the final answer to a problem and to have built a definitive and universally valid theory. Such experiences warn us to be far more cautious.

Despite considerable progress made since the early 1950s in understanding these phenomena, one cannot suppress a feeling of dissatisfaction. Building a coherent theory of the interrelations of economy and population requires continuous and careful appraisal of actual developments. Because of the practical complexity of such an undertaking, prejudice and facile theories always tend to have the upper hand. As a result, continuous observation of the facts leads to conclusions different from those currently held. These conclusions give food for thought. In particular, they suggest that economic research should focus on the working population and its problems rather than on finance, monetary policy, or materials. These latter are only the results of something else; as economic phenomena, they lie only at the surface, and lead all too often to neglect of the essential factor: men as producers and consumers. Statisticians, demographers, and economists should all work together to establish an all-encompassing, usable theory of population and economic development.

The term optimum population denotes a population of such size that, given this population, a specified indicator of “welfare” is maximized. This indicator may be output, or consumption per capita, or some more complicated social welfare function. How large a population must be to be of optimum size thus depends upon the content of the welfare indicator selected; it will be greater, in proportion, as population-oriented elements enter into this content.

Optimum size of population also depends, given some welfare index, upon other determinants of the value of this index. Thus, if W denotes this index, W = f(P,x1,x2,x3,xn),where P denotes population and the x denote other conditions, changes in which affect the value of W and could conceivably affect that value of P with which, under given conditions, the maximum value of W is associated.

The population P is therefore of optimum size when, with conditions x1x2x3 ... xn essentially constant, neither an increase nor a decrease in P can augment W. This optimum may not be invariant; a change in the ceteris paribus assumption may make greater or smaller the P with which a greater or smaller maximum value of W now is associated. The augmentability of the optimum is limited, however; a point is reached when further improvement in conditions x longer requires further increase in P for W to be maximized with respect to P, and thereafter such improvements increase W, but do not enlarge the optimum. A change in the value of W, dependent as it is on many sorts of change, does not indicate whether population maladjustment (defined below) is changing; it is only change in W, in relation to change in P (with other conditions essentially given), that indicates this. The optimum concept is applicable to sovereign states, regions within states, and metastates.

Optimum size and optimum growth rate. The advantages or disadvantages associated with a population’s being, or not being, of optimum size must be analytically distinguished from those associated with the process whereby a population changes size; for the former are associated with differences in population size as such, whereas the latter are associated with positive or negative population growth. Population growth, as such, may make for advantage; it also entails costs—costs in the form of the inputs required to train, accommodate, and equip population increments, as well as costs in the form of such unfavorableness in age composition as is associated with population growth. Further population growth is desirable, until an optimum size has been attained. Some of the rates at which this growth might proceed are preferable to others, and some particular rate might even be preferable to all the others. This last rate could then be designated as the optimum rate of growth, and alternative rates could be described as nonoptimal. This article does not, however, deal with this particular optimum or with advantages and disadvantages of population growth as such.

Population maladjustment. When the size of a state’s population deviates from what is optimum for it, such a state is experiencing population maladjustment. Let M, A, and O, respectively, denote degree of population maladjustment, actual population, and optimum population. Then M = (A – O)/O; and negative maladjustment signifies “underpopulation,” while- positive maladjustment signifies “overpopulation.” Although some of the circumstances that underlie O also condition A, O is looked upon as normally independent of A. Insofar, however, as changes in A generate changes in conditions underlying O, it may be said that O is functionally connected with A.

Yet, as a rule, changes in A do not produce such novel effects; they merely change the location of preferred positions on existing indifference maps, transformation curves, etc. To this statement, changes in A attributable to migration are most likely to be exceptions, inasmuch as such changes may produce changes in the technologies or the tastes of the affected countries. Underpopulation is more easily corrected than overpopulation as defined above; its correction merely requires population growth, whereas that of overpopulation depends on suitable autonomous changes (for example, in tastes, technology, external relations), whose occurrence may not be very probable.

History of optimum population theory. PreMalthusian writers occasionally complained of population maladjustment, but they did not define a population optimum or measure population maladjustment in relation to it. Presumably, they were not inspired by the attempts of Plato and Aristotle to fix what amounted to an optimum number of citizens for a Greek polis and, in addition, to indicate roughly how many slaves and noncitizens would be required. Malthus and some of his followers suggested the existence of an optimum; but they were concerned primarily with showing that positive population maladjustment is virtually inevitable, and that, consequently, it is essential to favor institutions that tend to retard population growth.

J. S. Mill ([1848] 1961, pp. 191–192) defined an optimum population, although he did not so name it: “After a degree of density has been attained, sufficient to allow the principal benefits of combination of labour,” he wrote, “all further increase tends in itself to mischief, so far as regards the average condition of the people.” Mill thus supposed the optimum would remain constant, although he implied that it had increased in the past. However, it was not until the late nineteenth century and thereafter that considerable attention was given to this concept, usually an optimum defined in terms of per capita income and reflecting a balance between “increasing returns” in manufacturing and related industry and “diminishing returns” in extractive industry. Whether increase in population was accompanied by increase in positive maladjustment, therefore, turned on which of these two forces was the more powerful.

On this issue, authors differed. Some expected that improvements in prospect were likely to increase optimums further. Others (for instance, Knut Wicksell) believed that populations in most, if not all, settled countries are of supraoptimum size and unlikely to derive much relief from optimum-increasing forces; they reasoned, therefore (partly on the basis of a generalized marginal productivity theory), that average income would increase most rapidly if growth in numbers was restrained and improvements in methods, together with increases in capital, were concentrated upon increasing output per head. Most discussions of the optimum were policy-oriented; they were designed above all to force proponents of population growth (of whom there were many in military, ecclesiastical, commercial, and other circles) to face the question, Cui bono?

In the 1920s, concern with overpopulation, stimulated in part by interpretations of the causes of World War I, intensified interest in optimum population theory. This interest declined somewhat in the 1930s, as the rate of natural increase fell in developed countries, only to be revived after World War II, as adverse effects of population pressure came to be more widely recognized.

Formal theory. Theory respecting optimum population must identify this population, given some welfare indicator, and it must account for the tendency of output to grow, under essentially ceteris paribus conditions, at a rate that both varies and differs from that at which population grows.

Specification of the optimum can then proceed as follows. Let the chosen indicator be output or consumption per capita; and let it be assumed that (within limits and for reasons examined below) output grows faster than population. This is assumed to be true even though output-governing conditions, other than increase in population, remain constant, with the exception of adjustment of input use to this population change, together with the distribution of activities in space and among occupations.

Then, to facilitate identification of the optimum, when population increases while other outputaffecting variables are held constant, let T denote total output; S, total savings or provision for capital formation; C, total consumption (C = T - S); and A, actual population. Let t and c, respectively, denote output and consumption per capita; and m, marginal output per capita (m = ∆t/∆a); then if T increases faster than A, with m increasing initially faster, and then slower, than t, t will be at a maximum when m and t coincide.

The population size associated with the coincidence of m and t is sometimes designated the optimum, although this designation is applicable only if there is no need, or incentive, to form capital, that is, when there is a glut of agents of production, complementary to labor, and with zero marginal productivity (as the equality of m and t implies). In all probable situations, however, these agents will be scarce and command a return, and further increments of capital will increase t; should the condition m = t accidentally come into existence, it would be unstable, for dissaving would result, and t, as well as the magnitude of the optimum, would decline.

A stable optimum population may coincide with the point of equivalence of m to c, a point at which a return, A(t – m), is imputable to the complementary agents and there are corresponding savings, S; this population is necessarily larger than that associated with m = t, since the marginal curve intersects the average consumption curve (which lies below the average output curve) to the right of where it intersects the average output curve. Even so, c will be about as high when m = c and S is saved as it would have been at the point m = t, had the state then impounded an amount corresponding to S and thus reduced actual consumption at that point. When c < t, the population optimum associated with m = c, although not unstable because of dissaving (there being saving), might increase in size as a result of the continuing capital formation made possible by savings, S. Given existing technology, this is only a possible outcome, however; for the increase in capital per head may raise t and c and yet not produce changes that increase the optimum. Indeed, many, and probably most, of the changes that increase t and c do not also increase the optimum, O, and do not therefore reduce population maladjustment, M; they merely make it more bearable.

The optimum is further increased when actual consumption is reduced not only by savings, S, but also by the more or less unavoidable use of resources for purposes other than the supplying of the domestic population with consumer goods and services and capital. Illustrative of this is the employment of resources for the supplying of security against possible foreign enemies, or for the support of unproductive idlers, or for unilateral payments of tribute and so-called economic aid to foreign states. Let all such outlays be denoted by L; then consumption, C, on the part of the productive population (hitherto supposed to embrace all persons), becomes not T – S but T – S – L. Accordingly, m will coincide with average consumption (T – S – L)/A at a point lying to the right of the point where c approximates (T – S)/A; the population of optimum size will be larger, therefore, and t will be smaller when L is positive than when L is zero. In general, threats to a nation’s security enlarge its optimum-size population and diminish its average consumption.

Values underlying choice of optimum. A nation’s population optimum is further enlarged when it seeks to maximize not, for instance, consumption per capita but some other social welfare function into which populousness enters as a substitute for output or consumption—or, in other words, up to the point where a further increment in populousness does not compensate for the diminution in per capita income and consumption associated with it. The size of the optimum population corresponding to this point depends on how powerful are the tastes favoring populousness; it may occasion problems not associated with smaller optimums. Thus when this optimum is reached and families can therefore average barely more than two children, unsatisfiable tastes for children may occasion discomfort. This optimum also conduces to relatively greater inequality in the distribution of pretax income (although this can be offset by differential taxation) than do smaller optimums. Moreover, it would result in greater positive population maladjustment, should tastes for populousness decline markedly.

Of more fundamental concern than these various formulations is the rationale underlying “increasing returns,” or the sometime tendency of output to increase faster than population or the labor force (here supposed to constitute a constant fraction of the population), even though other conditions (technology, capital stock, etc.) remain unchanged. One source of this tendency is the indivisibility of some complexes of agents of production with which labor in general is combined, such as the transport system or much of the apparatus of state. Indivisibilities of this sort are most important when over-all population density is low; they become of little or no importance after density has become relatively high, even though quite lumpy increments are sometimes added to a nation’s equipment. The second, and principal, source of this tendency is extension of the market, together with facilitation of the extension of various forms of the division of labor. Within limits, enlargement of the labor force permits greater technical subdivision of productive activities in economic and geographical space and, at the same time, by providing an enlarged market, makes much of this subdivision sufficiently profitable to warrant its undertaking. A point is finally reached when numbers are sufficiently great and average income is sufficiently high to provide as large a market as is required to support the best of current and prospective technological possibilities. This point will be approached at a rate proportionate to the speed at which small-scale plants and firms become as efficient as large-scale undertakings, and as international and interregional trade remains unimpeded and, hence, able to add, for particular products of specialized undertakings, external to internal markets.

Some limiting factors. In the past, it was supposed that discovery and invention were positively associated with population density, up to a point, because interpersonal stimulation and communication were facilitated by increase in density. This supposition, while not without limited validity, is now seldom of much import; today, international interchange of technical information, together with improved internal means of communication, supplies most of the stimulus and information essential to discovery and invention.

To the limits to “increasing returns” already noted—namely, the overcoming of indivisibilities and the exhaustion of benefits consequent upon extension of division of labor and markets—there must be added a third: the emergence of factors that may become operative even before the other two limits are reached. This third type of limit becomes operative when whatever inputs have been available gratuitously (for example, fresh water) or under conditions of constant supply price either are no longer susceptible to further increase in supply or are susceptible to such increase only under conditions of rising real cost. While the advent of such a limit may be partially counterbalanced by substitution at the technological, as well as the consumer, level, it is never wholly counterbalanced save through technological changes that often, and perhaps usually, are the result in large part of input investment that might otherwise have been used to increase average output. Furthermore, should the limitational factor or its replacement be a wasting resource (for example, fossil fuels), its scarcity would increase more rapidly than otherwise, and so might prove less susceptible to technological alleviation.

It is doubtful if the populations of many advanced countries (barring such countries as Australia and South Africa) are of less than optimum size, given that consumption per capita is the indicator to be maximized. It is probable that technological improvements, together with increase in capital per head, have long been almost entirely responsible for increases in output per man-hour and that larger populations have not been essential, or in a free-trade world would not have been essential, to the optimum exploitation of these improvements. It is now quite possible, furthermore, that additional technological improvements, together with increase in capital per head, may reduce the optimum size of population. Should this come about, both positive population maladjustment and average consumption will increase, as, indeed, they seem to have been doing for many years. Maladjustment will increase further, of course, as physical environmental limitations to growth of output make themselves felt.

Tendency to optimum. Although some authors have suggested that populations tend to assume optimum size, this inference is of quite limited validity. Populations are likely to respond significantly to changes in the degree of population maladjustment only if these changes generally modify the ability of men to satisfy their aspirations and only if men can respond thereto by regulating their fertility or otherwise controlling their numbers. This sort of regulation is possible in a country in which control of the apparatus of state is highly centralized and the welfare function to be maximized is one prescribed largely by those in control of this apparatus; powerful incentives, deprivations, and propaganda can then be used to modify fertility and perhaps also mortality. In a modern state in which individual sovereignty is great, however, increase in population maladjustment is likely to make for a decline in fertility only if such an increase slows down the rate of growth of average income more than the rate of growth of the aspirations to be realized through the expenditure of this income; for then, family size, if not the rate of family formation, will be subjected to greater restraint.

In underdeveloped and backward states, a contrasting situation may be encountered. In these states, an increase in positive population maladjustment is likely to be accompanied by a diminution in the rate of population growth, when, even under optimum conditions, average income supplies little beyond pressing needs. An increase in population maladjustment then tends to lower average income somewhat, and hence to worsen mortality, as well as to intensify some of the restraints to which fertility is subject.

The optimum and policy. Theory relating to the optimum, as such, is not very well adapted to the formulation and execution of population policy, even though population maladjustment is very common and the marginal social benefit of population growth seldom coincides with the marginal social cost of such growth. It is rarely, if ever, possible to determine precisely what population size is optimum for a country, under given conditions; and it cannot be supposed that these given conditions will be static. Nor is it possible to “zero in” on the optimum point, after the manner of revealed preference theory. It is possible, however, given some welfare index and working criteria of changes in this index, to narrow the zone within which the definied optimum almost certainly lies. One may choose a tentative optimum point, inquire carefully if a larger or a smaller population is desirable, and then move this point in whatever direction reduced maladjustment seems to lie. There will emerge an “optimum” zone, within which the true optimum may be assumed to lie. Even though the precise location of the true optimum is not determinable, it may be assumed that welfare per capita at any point within this zone is not likely to be notably different from that associated with any other such point.

Some believe, however, that the smallest of the populations lying within such a zone are the ones to be preferred; then the rate at which depletable resources are used is depressed, and (should technological or other changes make for a reduction in the magnitude of the optimum) positive maladjustment almost certainly will be less than it would have been had the larger of the populations lying within the optimum zone been chosen. This belief rests upon the supposition that whereas a condition of underpopulation is easily remedied, one of overpopulation often is irremediable.

If the actual population of a country corresponds to one lying within such an optimum zone, it may be inferred, when there is little uncertainty respecting the boundaries of the zone, that further population growth is not desirable; and this inference becomes all the stronger when the actual population corresponds to one situated in that portion of the zone where the largest populations are found. It is then highly probable, given the welfare function chosen for maximation, that the marginal social cost of a further increment in population would outweigh its marginal social benefit. Under these circumstances, it becomes clearly desirable, should the marginal private benefit of population growth still appear to exceed its marginal private cost, to introduce incentives and deprivations suited to bringing these benefits and costs into balance.

It is not likely, however, that such action would be taken in the typical polity where short time-horizons, ideologies, and superstitions play important roles. While modern governments may subsidize family planning, they tend to more than offset this by somewhat easing tax burdens and costs associated with the production and rearing of children. It is to be expected, therefore, that the net effect of government policies will almost invariably be to re-enforce the forces making for positive population maladjustment, until it becomes very pronounced.

The term “population composition” refers to the various social and biological categories into which the members of a population may be classed. The composition of a population at any one time is not only a reflection of its social history but also an indicator of the kinds of social problems that it will face in years to come. It is therefore of great interest to governments to obtain, by means of censuses, systems of vital registration, and so forth, the most complete and most accurate information possible concerning population composition. The analysis of population composition forms an integral part of demography, the science of population.

Although the number of traits that distinguish one person from another is theoretically unlimited, the number of individual characteristics generally included in the study of population composition is rather small. Only characteristics that are socially and demographically relevant are considered, and even then the technical and financial problems of recognizing and recording individual attributes tend to impose stringent limitations. The characteristics by which populations are usually classified include such basic demographic variables as age, sex, and marital status, and such elementary indicators of social organization as nationality, race or color, language, religion, education, labor-force status, occupation, and industrial classification. This information, as already stated, is generally gathered by means of census enumerations and through the registration of births, deaths, and marriages. Although the “vital statistics” generated by the latter method refer only to people who have experienced a vital event in a given year, they can be used to estimate certain characteristics for the total population and, thus, to maintain a continuous inventory of characteristics. For example, the registration of births and deaths by race permits a fairly accurate estimate of the racial composition of the population in intercensal periods. Another source of information, of growing importance, is the sample enumeration (or microcensus, as it is called in some countries), which provides data needed in intercensal intervals and also permits questioning about characteristics that cannot be included in complete enumerations.

The specific population characteristics included in census and other official statistics vary from nation to nation, depending upon their relevance in each case. Thus, questions about race or language are omitted in countries which are ethnically homogeneous; likewise, questions about literacy have been deleted from the censuses of many advanced nations. On the other hand, some governments, for reasons of policy, deliberately omit certain important characteristics from their enumerations. For example, no question has ever been asked about religious affiliation in the United States decennial census, because of a rigorous interpretation of the constitutional separation between church and state. In India enumeration of caste membership was dropped after independence, as a matter of social policy.

Sex composition

Most easily measurable, and of fundamental importance both demographically and socially, is a population’s composition by sex. In any given area the distribution of the sexes tends to be unequal, owing to the operation of any or all of three factors. First, a differential sex ratio at birth is universal; more males are born everywhere than females. On the other hand, at all ages the death rates for males are usually higher than those for females. Finally, migration is sex selective; in long-distance migration males tend to outnumber females, but in short-distance movements females usually predominate.

The most frequent measure employed in the study of sex composition is the sex ratio: the number of males per 100 females. It is easily computed by dividing the number of males in the population by the number of females and then multiplying by 100 (in European countries the ratio is often expressed

as the number of females to a hundred males). Table 1 shows the sex ratio of a number of selected countries throughout the world. It indicates a variation from less than 87 males per 100 females in Austria to 111 males per 100 females in Ceylon and Pakistan. The countries where the sex ratio exceeds 100 fall into two distinct groups. First, there are underdeveloped areas, where females in the childbearing ages have higher mortality rates than males. In this category belong such countries as Ceylon, Pakistan, Libya, Tunisia, and India. The second group consists of countries which have experienced large-scale immigration which is predominantly male. This explains the relatively high sex ratios of Israel, Malaya, Argentina, Australia, Canada, and New Zealand, for example, and of Cuba and Panama, which have attracted young male laborers from other Caribbean countries. An unusual case is that of Ireland, a country with the relatively high sex ratio of 101.9. The explanation probably lies in the fact that emigration from Ireland is predominantly female; citizens of Ireland may enter the United Kingdom freely, and young Irish women avail themselves in large numbers of the opportunity to obtain positions in the neighboring country.

At the other end of the scale are the countries with low sex ratios. The imbalance of the sexes in those countries is the result of a combination of war losses and long-standing emigration. France, Germany, and Austria have been heavily affected by war losses, whereas emigration has played the greater role in accounting for the low sex ratios of the United Kingdom and Italy, for example.

In countries where migration plays a minor role, the sex composition is determined almost entirely by the interplay of birth and death rates. In the industrially advanced countries the sex ratio at birth is usually around 105 or 106, but mortality differentials favor females at all ages, so that the sex ratio declines steadily with advancing age and reaches 100 between the ages of 40 and 50. The total populations of these countries tend to have sex ratios between 94 and 97. In the underdeveloped countries maternal mortality is high enough to offset the lower mortality rates of older females; consequently, the sex ratio for the total population in such areas averages around 100.

Migration also exerts a powerful influence upon the sex ratio within a given country. Internal migration generally consists of short-distance movements, which in their net effect shift the population from rural to urban areas. Urban migration usually includes more women than men. Occupational opportunities open to women are greater in urban areas; women are therefore strongly attracted to the cities. As a result, sharp differences may arise between the sex ratios of rural and urban areas. In general, cities have low sex ratios, while rural–farm areas have high ones. There are, however, some exceptions; cities which are steel or mining centers or naval bases have high sex ratios.

The ratio of the sexes in a given area has an important bearing upon the incidence of marriages, births, and deaths. The number of possible marriages depends in part upon the proportion of the sexes in the marriageable ages. The surplus of women in the urban areas reduces their chances of finding a marriage partner, whereas their shortage in rural areas may create difficulties for eligible young men. An imbalance of the sexes will delay marriage and reduce the number of legitimate births. Because mortality rates among males tend to be higher than among females, a disproportionate sex ratio also affects the over-all death rate.

Age composition

Age, as well as sex, is a primary characteristic of the individual. Since it is related to physical capacity and mental maturity, every society uses age as a major building block in its social organization. Social roles and responsibilities are assigned in accordance with an individual’s age. The age composition of a society, therefore, determines the number of people available for important social categories. Of special importance here is the size of the labor force and of those groups wholly dependent upon the working force—children and the elderly. In addition to serving as an important basis for the ascription of social status, age is biologically related to fertility and mortality.

The obvious connection between age and a wide range of demographic and social phenomena makes the classification of a population by age groups especially important. In conjunction with sex, the age distribution provides the basis for all detailed demographic analyses. Birth and death rates can be meaningfully compared and interpreted only when the age and sex composition of the population is taken into account. It is likewise indispensable for the construction of life tables and for making population projections.

Data on age are less reliable than sex data. In nonliterate societies individuals often do not know their age, and census takers have to resort to estimates. Even in literate populations there is a definite tendency for respondents to concentrate on numbers ending with zero or five, and on even numbers. For purposes of refined analysis it is, therefore, necessary to calculate correction factors to offset the effects of age heaping.

The current age structure of any population is the product of birth, death, and migration rates which have operated in the past. A comparison of the age composition of various countries, illustrated in Table 2, shows the existence of wide variations between different parts of the world. One can distinguish several major types of age structures. At the one extreme are the underdeveloped countries of Asia, Africa, and Latin America, which encompass most of the surface of the earth and include the greater part of the world’s population. These countries, characterized by high fertility and high mortality rates, have a very similar age composition. They all have a high proportion of children—approximately two-fifths of their population is in the 0–14-year age group. Over one-half the population is in the 15–64-year age range, which contains most of the economically active people. The proportion of people over 65 years is quite small, generally below 4 per cent. The high proportion of children means a heavy dependency burden on the economically active members of the population.

At the other end are the economically advanced countries of northwestern and central Europe, North America, and Oceania, where birth and death rates are both low. In these countries children under 15 years constitute only one-fifth to

Table 2 – Percentage distribution of selected populations by three broad age groups

one-fourth of the total population; about two-thirds of the population are in the 15–64-year age range; and the proportion over 65 ranges from 8 to 12 per cent. These age structures are the result of major fertility declines, which have had the effect of sharply reducing the proportion of children and increasing, first, the percentage of persons of working age and, in time, that of the aged. The popula tions of France and Sweden, for example, where the decline of the birth rate began early, were already comparatively aged at the turn of the twentieth century. But in most countries of this group the modifications of the age structure a relatively recent phenomenon. In the New World substantial immigration has also contributed to enlarging the proportion of adults in the 15–64-year age range. The result has been an immediate economic advantage, since this has meant a light burden of dependency on a broad base of economically active age groups. However, the reduction of fertility means that the present extraordinarily broad groups of people in the working ages will not be fully replaced in the near future. Consequently, the proportion of those over 65 will continue to rise.

A third group of countries are now in a transitional stage. After drastic reductions in their mortality, these countries have recently begun to experience substantial fertility declines. Analyses which have measured the effects of changes in mortality and fertility separately have shown conclusively that fertility is the main factor that affects the age structure of any given population. Countries with currently declining fertility will therefore experience a progressive aging of their population: Japan and some eastern European countries are cases in point. As economic development progresses, other countries will also enter the transitional phase; but the age structure of the presently underdeveloped countries is not likely to change appreciably in the near future.

In the economically developed countries the phenomenon of aging has attracted widespread public attention, since it has created considerable social and economic problems. In an agricultural economy societies have a familistic social organization. There the aged not only are maintained within the family household but occupy a high social status. By contrast, in industrial societies the aged are in a much less enviable position. They tend to maintain separate households and to drop out of the labor force, often involuntarily. They can play fewer socially useful roles, and those who cannot live on their savings become dependent upon their children or the state. These changes in status have had not only economic but also major psychological repercussions, which require attention and amelioration. The situation was viewed with considerable alarm in the 1930s, when the birth rate of most Western countries reached a new low and the populations of many of them appeared to be aging very rapidly. The postwar resurgence of the Western birth rate, however, has reversed the trend and resulted in a measure of population rejuvenation in a number of countries—for instance, France and the United States. Nevertheless, the absolute number of old people continues to rise, and the concern about their welfare is greater than ever.

Age composition and the incidence of aging vary also among subgroups of the population within a given country. Age differentials exist whenever groups exhibit different fertility and mortality levels; their age structure is also affected by migration. Thus, the rural-urban migration of the younger age groups causes rural populations to be older, on the average, than city populations. Considerable differentials are often found, also, between various ethnic and religious groups. For example, the higher fertility of Roman Catholics gives them a younger over-all age structure than that of Protestants or Jews in the same countries. Differential mortality also creates significant age differences between the sexes. In the developed countries females live, on the average, from four to seven years longer than males; consequently, in such societies the proportion of old women is considerably higher than that of old men.

Marital status

In every human society the family functions as the basic unit, charged with the continual replacement of the generations. This involves not merely procreation but also caring for the children over a long period of time and training them for the performance of socially useful roles. Because of this important part played by the family, information about the marital condition of the population is generally included in official census enumerations, and changes in family formation are carefully studied by demographers, sociologists, and economists. Differences in marital status have a direct bearing on both fertility and mortality. The age at which people get married and the proportion of the population that eventually gets married is an important determinant of fertility, since in general fertility is higher in places where marriages are concluded early and where the proportion married is high. Mortality also varies with marital status; both married males and married females have lower death rates than do unmarried persons of the same ages. In part these differentials arise from the fact that marriage is selective of individuals in better health. Partly, however, the greater longevity of the married may result from the better personal care and greater regularity which usually characterize married life.

International comparisons of marital status require considerable caution because in certain countries a high proportion of couples live in consensual unions and may or may not report themselves to the enumerators as married. This problem exists in all countries, because of those who are legally or de facto separated. As a result, the number of married males is not equal to the number of married females in the census statistics of any country. Despite these difficulties of classification, the percentages of married people in various age groups, as reported by their respective national censuses, show some interesting variations. First of all, there are great differences in the age at marriage, as can be seen from the data presented in Table 3. India and Turkey, for example, show pronounced patterns of early marriage, whereas the tendency to postpone marriage is clearly evident in such countries as Ireland, Spain, and Japan. In addition, there are substantial variations in the frequency of marriage. The proportion married at different ages undoubtedly reflects variations in social organization and in cultural patterns between different societies; but the connections between marital status and social structure are complex and do not permit easy generalizations.

The only generalization which applies universally is that the percentage married reaches its maximum for females at an earlier age than for males. As Table 3 shows, women in the 15–24-year age group are much more likely to be married than men. However, after the age of 35 the proportion of married men exceeds that of married women everywhere except in Ireland, where male celibacy is unusually high and the reversal occurs only after age 44. In all countries the disproportion becomes quite pronounced after age 45 because the number of widows increases much more rapidly than the number of widowers.

As in the case of age and sex composition, there also exist differences in marital status between subgroups of the population within a given country. Perhaps the most pronounced differentials are the residential ones which are the effects of migration. The cities attract a disproportionate percentage of unmarried women but a relatively low proportion of single men. By contrast, the suburbs and

Table 3 – Percentage married in selected countries, by age group and sex

Occupational composition

When we turn from the more strictly demographic to the social attributes of a population, it cannot be denied that occupational status assumes a place of paramount importance. Men do not live by bread alone; but the need to make a living requires the sustained effort of a very substantial proportion of the population in all societies. Moreover, the way this living is made largely determines the general social and economic position of the worker and his family. Lastly, the classification of workers by occupation and industry provides a major measure for any comparative analysis of the stage of economic development reached by different societies, as well as an index of regional differences within a given country.

Labor-force status

The first step in the analysis of occupational characteristics is the separation of the total population of a country into two groups —those who are economically active, also called the working force or labor force, and those who are economically inactive. Actually, this distinction is hard to make in primitive societies or in grossly underdeveloped areas, where the low level of technology forces virtually the entire population to participate in the production of goods and services. However, with the rise of a market economy, there is an increase in the proportion of people who consume goods and services but do not produce them, and the distinction between economically active and inactive becomes significant. Yet even in highly developed societies it is no easy matter to delineate adequate criteria for distinguishing between those who are economically active and those who are not. [SeeLabor Force, article ondefinitions and Measurement.]

These difficulties notwithstanding, statistics on the labor force are included in the census tabulations of most countries. Although different countries vary considerably in their definitions and classification procedures, these differences affect mainly the statistics for women, youths, and aged persons because these are the groups in which relatively large proportions of workers are engaged in unpaid family work or work only part time, seasonally,

or intermittently. By contrast, the statistics for men in the working ages are much more comparable, because the overwhelming majority of males in these age groups are economically active. Indeed, the proportion of males between the ages of 20 and 60 years who are in the labor force in various countries is almost uniform. Thus, in the 20 countries listed in Table 4, which represent widely differing social and economic structures on six continents, the proportion of men aged 20–59 years who are economically active ranges from 91 to 99 per cent. By contrast, labor force participation rates for women range all the way from 13.3 per cent for Brazil to 99.3 per cent for Egypt, with 15 of the 19 countries reporting less than half of the females in this age range as economically active.

The total size of a country’s economically active population depends to a large extent on the size and on the age and sex composition of the total population. Demographic factors establish the maximum limit of the number of people who can participate in economic activities. Such factors are the principal determinants of the size of the male labor force, since in all countries nearly all males pursue some gainful activity from the time they enter adulthood until they reach old age. However, the number of women, young people, and old persons who are economically active is strongly affected by a variety of nondemographic, cultural, and economic factors. The type and organization of economic production, the level of income, and the relative value placed on such noneconomic activities as formal education, retirement, child rearing, and leisure-time pursuits strongly influence the labor-force participation rates of these three groups. In underdeveloped countries, children begin to work at a tender age and few old people can afford the luxury of retirement. In industrially advanced nations, almost all youths are in school until they are 16 or 17 years old and a sizable proportion continue their formal education well into their twenties, while pension plans facilitate and often force the retirement of the elderly. The extent to which women participate in the labor force depends on the type of employment available to them, their marital status and childbearing patterns, and the degree of their social emancipation.

Industry and occupations

In addition to separating the total population into the two basic categories of those who are economically active and those who are not, most national censuses further classify the economically active according to the industries in which they are engaged and the types of occupations they follow. The relative distribution of the labor force by major lines of endeavor, such as agriculture, manufacturing, trade and commerce, transportation, and service, provides one of the most useful indicators of the stage of economic and cultural development a particular society has attained. The same is true of the division by major occupation groups, such as professional and technical workers, managerial and clerical employees, sales workers, farmers and fishermen, craftsmen, industrial operatives, laborers, and service workers. Major shifts have occurred in the occupational composition of all economically advanced countries as the processes of urbanization and industrialization have proceeded. The proportion of the labor force engaged in agricultural activities has declined rapidly, while the percentage engaged in manufacturing, trade, transportation, and services has sharply increased. In the United States, for example, in 1840 nearly 70 per cent of the economically active were in agricultural occupations; a century later the proportion had fallen to less than 20 per cent. Under the impact of technological change, the redistribution of the labor force is a continuing process.

Unfortunately, national variation in the definition of the various industry groups and in the content of the occupation categories greatly limits the validity of international comparisons. Nevertheless, a rough measure of the relative degree of industrialization can be readily obtained by comparing the proportion of the male labor force engaged in agriculture. The smaller the percentage of men engaged in agriculture, the more highly developed is a country’s economy. The proportion of males in the labor force who are engaged in agriculture is shown in column 3 of Table 4. Although these 20 countries show remarkable uniformity in the percentage of their male population who are economically active, they diverge widely in degree of industrialization. Countries like the United Kingdom, Belgium, the United States, and West Germany all have reached an advanced stage of industrialization, with less than one-sixth of their male labor force engaged in agriculture. In sharp contrast stand underdeveloped areas like Bolivia and Brazil, where two out of every three males are still occupied in agricultural pursuits.

Educational status

Next to occupation, to which it is closely related, education ranks as an element of major importance in the composition of modern populations. The educational achievements of an individual largely determine his level of living, his cultural opportunities, his social status and prestige. They influence his health and survival chances, his mental attitudes, and his entire outlook on life. By the same token, it is well recognized that the degree of literacy and the total amount of schooling received by the population as a whole plays a major role in its social, cultural, and economic well-being and influences the rate of its development. Educational status therefore serves as a most useful index of the socioeconomic position of individuals and of the class composition of a whole society.

Educational data are collected by the censuses of most nations, but until recently the amount of educational information has been quite limited. The simplest and most widely available measure of educational status is the proportion of the population unable to read and write [seeLiteracy], In most advanced countries illiteracy has been almost eliminated, and therefore questions on literacy are no longer included in population censuses. Thus, the data for Sweden stop with 1930, and those for Canada stop with 1931. Illiteracy still constitutes a serious problem, however, in many countries.

Because literacy rates are merely crude approximations of educational achievement, an increasing number of national censuses have recently begun to employ more refined measures. They ascertain the number of years of school completed by each respondent and the proportion of the population in specified age groups who are attending school. Unfortunately, the great diversity in the structure of national education systems precludes any valid international comparisons. Within a given society, however, statistics on years of school completed, cross-classified by age, sex, residence, and other characteristics, serve as very useful indexes of cultural achievements and of needed improvements. In the United States, for example, the median level of school years completed by the total population 25 years of age and over rose from 8.6 in 1940 to 10.6 in 1960. Particularly significant is the fact that the proportion of those who have at least some college education rose even more steeply, from 10.1 per cent of the total population 25 years of age and over in 1940 to 16.5 per cent in 1960; in the same 20 years, the percentage of college graduates increased from 4.6 to 7.7. The trend of college enrollment has been rising very rapidly since World War II. Of all American students who were graduated from high school in 1959, 42 per cent were enrolled in college in 1960, on either a full-time or part-time basis. In the United States a higher education may soon become the rule, rather than the exception.

Although educational gains have been widely shared by males and females, rural and urban population, white and nonwhite groups, there still persist sharp differences in the average level of schooling. In 1960 the median number of school years completed by the nonwhite rural farm population was only 5.7 years, or just about half the 11.5 years of the urban white population. This extreme contrast proves that even a country like the United States, where educational progress has been rapid and widespread, still has far to go before all elements of the society are assured a reasonably adequate amount of schooling.

Ethnic and religious composition

Most of the remaining population divisions that have major demographic and social significance refer to ethnic and religious differences. Cultural diversity generates differentials in fertility, mortality, migration, marriage patterns, educational attainments, and socioeconomic status. In many societies, therefore, classification by ethnic and religious characteristics is essential for any useful analysis of population data. Thus, as the data in the preceding paragraph indicate, a meaningful analysis of the educational status of the United States population should show statistics subdivided not only by age, sex, and residence but also by race.

The divisions created between different segments of a population by religious differences have ranged all the way from violence and warfare to segregated school systems. In most Western countries religion now plays a less drastic role than formerly; but there are some exceptions. In the Netherlands, for example, Roman Catholics and Protestants have developed an almost completely dual social structure, from separate schools to separate labor unions and separately organized leisure activities, including sports. In most other nations, the influence of religion has become attenuated and individuals often are not consciously aware of it. But its effects on behavior patterns still persist in many subtle ways; in the United States, for instance, most fertility differentials have declined noticeably in recent years but differences between Roman Catholics and Protestants remain undiminished.

The most important characteristics with respect to which ethnic groups are usually compared are race, color, national origin, and language. In immigration countries all of these factors, in various combinations (and often intertwined with religion), give rise to important cultural differences. In such countries, place-of-birth statistics are useful in identifying immigrant minorities, and in highlighting problems of acculturation and assimilation. In most areas which have been subjected to conquest and colonization by Europeans, race or color differences divide the population into several segments, which remain sharply differentiated in all demographic and social respects. In all such countries statistical breakdowns by race are indispensable for demographic and sociological analysis.

In most of Europe, of course, racial composition is not as important as in areas of European colonization, but nationality and language differences play a prominent part in many countries. The history of Europe abounds with incessant clashes over nationality differences, which have resulted in numerous wars and frequent persecution of national minority groups. The outstanding exception to this pattern of conflict is modern Switzerland, where four language groups and the adherents of three major religions have long been integrated into a stable and harmonious unity without losing their distinctive identities. By comparison, the animosity between the Belgian Flemings and Walloons, which shows no signs of abating, appears a curious anachronism in the very center of the rising European Community.

It is likely that in the long run the all-pervasive processes of industrialization and urbanization will have the effect of imposing a similar socioeconomic structure upon most, if not all, societies, thereby greatly attenuating the importance of internal ethnic and religious diversity. In the meantime, however, statistics on nationality, language, race or color, and religion remain indispensable in most countries, not only for analytic purposes but also for the making of social policy.

Affairs 1956 The Aging Population and Its Economic and Social Implications. Population Studies, No. 26. New York: United Nations.

United Nations, Department of Social Affairs, Popu Lation Division 1953 The Determinants and Consequences of Population Trends: A Summary of the Findings of Studies on the Relationship Between Population Changes and Economic and Social Conditions. Population Studies, No. 17. New York: United Nations.

Population is in essence a quantitative concept used to denote aggregates of various kinds. The study of population distribution is concerned with how and why the unit parts of such aggregates are distributed over space in one way rather than another. Particular patterns of population distribution are seen to be closely associated with varying rates of population growth and migration. As applied to human beings, this topic has obvious theoretical and empirical interest, not only for sociology, but also for economics, anthropology, political science, and all those disciplines concerned with the organization and structure of communities, regions, economies, or other groupings that denote relatively stable patterns of human settlement.

In the study of any population, emphasis can be placed either on the whole or on its parts. Historically studies of population distribution have shown a strong tendency to involve a restricted area, such as one city or one section of a country, and, at least until recent years, they have been descriptive rather than analytical in scope (Bogue 1959). Many are case studies of the size and composition of the populations of minor divisions within a state or district or of changes in these over time. Quite often, population trends in a local area are contrasted with those in some larger region of which the area is a part.

Measuring population distribution

The concern of geography with space has been clearly demonstrated for a long time. It is not space itself, however, that is of interest to the geographer, but rather the persons and objects occupying space and their relations to each other and to a habitat.

The conventional method which geographers have used to present data on population distribution is mapping. Various cartographic techniques, such as dot maps and linear-distance maps, have been developed (James 1954). Although these have a certain convenience, they lack precision and are useful only as first approximations to understanding the distributions they depict. However, their utility is enhanced when they are used in conjunction with statistical measures of various kinds. Obviously maps, charts, and tables are dependent on the collection of census data or on data from registration systems or special surveys. They are no more than graphic representations of the basic figures on distributions of populations. It must be emphasized that any measures which summarize the distribution of population are likely to be strongly influenced by the choice of area for the collection of data. [SeeGraphic Presentation.]

Measures of density

All measures of population distribution are concerned with variations in numbers or characteristics of a population over time or by place. The simplest measure is a ratio of numbers to land area. Where information on number of people and amount of land is available, it is a simple matter to use the ratio P/A, population divided by area, to yield a population density. So crude a measure is only slightly improved by substituting population per square mile of arable land. Furthermore, density ratios are averages that give no indication of significant internal variations. Nevertheless, countries, provinces, and other areas are often compared in terms of relative degrees of concentration or dispersion of population by the use of a series of density ratios.

Such comparisons may be useful when there is a rather high degree of both geographic and cultural uniformity among regions. Just the opposite, however, is frequently true. In consequence, ratios of population density are often not comparable. In the absence of other information it is not very helpful to know that in 1961 the population density of the United Arab Republic was 27 times that of Australia. Such a figure must be interpreted, and it is of little consequence that large areas of both countries are uninhabited desert. What is significant is that there exist differences in social and economic organization which produce quite diverse patterns of land utilization and dissimilar functional relations with external areas. Both of these result in differences in ability to provide support for the population of each country at particular levels of living and in specific distribution patterns.

Around the world the highest densities are found at two extremes. In crowded underdeveloped countries both fertile lands and nearby large commercial-industrial cities support dense populations at low levels of living. In modernized nations the highest densities appear in and around those large cities that are best situated to mediate in the exchange of goods and services on a national and world-wide basis and, by so doing, to support their people at relatively high levels of living.

Measures of spacing

In addition to density ratios, various other measures of spacing and concentration are employed to indicate the extent to which numbers are massed or dispersed over a given territory (Duncan 1957). The Lorenz curve has been adapted to measure variation in population distribution, and related indexes of concentration and of dissimilarity have been developed. The fundamental problem remains that when different sets of areas are used as a base, different and even opposing results may be obtained. Consequently any interpretation of an index of this kind must be directly related to the system of subareas adopted.

Measures of spacing have evolved both from the community studies of plant ecologists and from the economists’ use of models of areas within which an even distribution of population is hypothesized. Various centrographic methods measure central tendency by computing centers of population or of activity. Such measures have been popularized by their use in census volumes, particularly in the United States. The mean center conveniently summarizes the distributions within a particular area at one or more points in time. Simultaneously computing the centers for several different groupings, such as population, urban population, ethnic groups, farm population, and manufacturing, will summarize general trends within a region. However, the choice of the mean point (center of gravity) or some alternative device, such as centilides or quartilides, will depend on the problem under investigation. [SeeGeography, article onstatistical geography.]

Using an analogy from physics, John Q. Stewart and William Warntz (1958) have described the structure of particular population distributions by the use of population potential models expressed by the coefficient N/d, numbers divided by distance. These are measures of the influence, or “drawing power,” of people at specific distances from one another. They are illustrated by the attraction of a major population center for migrants initially located at various distances. Finally, use has been made of several categorical measures that involve the classification of populations by size of community, distance from designated centers, rank-size, function, and so on. Examples are the division of urban centers into metropolitan and nonmetropolitan and of villages into industrial, agricultural, and suburban. The population distribution “found” by the categorical approach will depend heavily on the scheme chosen by the investigator.

World population distribution

The single most striking fact about the distribution of the world’s population is its unevenness. Roughly nine-tenths of all people are crowded into no more than a quarter of the land surface. There are three broad areas of heavy massing of population. The most prominent is in Asia, where the most densely populated areas are Japan, South Korea, mainland China and Taiwan, Java (in Indonesia), India, and east Pakistan. Also heavily settled are the greater part of the European peninsula, the northeast coast and Great Lakes rim of the United States, and parts of the Caribbean and of coastal South America. Non-Soviet Asia, which constitutes not quite 20 per cent of the land surface of the globe, is occupied by an estimated 60 per cent of the world’s people, and this percentage is increasing. By contrast, South America, with 13 per cent of the land surface, presently accounts for only 6 per cent of the world’s people. It too is growing at a rapid rate.

Differences among areas in natural or social conditions produce marked variability in the degree of population concentration. The causes are in part geographic. The significance of climate as a determinant of population distribution, a theme familiar since Montesquieu, was enlarged upon in the nineteenth and early twentieth centuries by such geographers as Friedrich Ratzel. Not only do climatic conditions limit the spread of population by maintaining arctic, desert, and tropical areas where settlement of any sizable numbers is difficult or impossible, they also influence the fertility of lands, such as the valley of the Nile or the flood plains of the Ganges, where natural conditions encourage a massing of human beings. Similarly, topographic features may provide favorable or unfavorable conditions for settlement. For instance, only a minute fraction of the world’s people live at any great altitude above sea level.

In the modern world cultural factors are of greater importance for population distribution than all but the most extreme geographic conditions. The existence of local natural resources may be an immediate cause for the settlement or rapid development of specific areas. Nevertheless, iron ore, coal, and other natural resources have no real significance except in a culture technologically and economically able to exploit them. The growth of large communities on favored coastal and river sites is a function of the development of trade, particularly of industrial commerce. In both cases the likelihood of concentration of population at a given point will be related to the existence of competing sites and to the requirements of an economy for specific raw materials or finished goods. The size, and even the existence, of particular places will also vary according to such outside conditions as economic costs, transport time, or changing routes and market requirements.

Distribution of urban population

Marked changes in human organization are reflected in the redistribution of population into an increasing number of larger centers. Between 1900 and 1960 alone the number of cities in the world with more than a million inhabitants increased from 10 to 63. Around 18 per cent of the people of the world now live in cities with populations of 100,000 or more. This urban trend has been accompanied in the modernized nations by a precipitous decline in the proportion of the population living on farms. In the United States, for instance, only some 5 per cent of the population lived in places with 2,500 or more people in 1790, when the first census was taken. By contrast, in 1960, 70 per cent lived in such places or in the built-up fringe of large urban centers. Farm families made up 95 per cent of the population in 1790 and only 9 per cent in 1960.

Rapidly spreading urbanization, as well as the concentration of population in an increasing number of growing cities, has had an obvious and profound effect on population patterns, not only in Europe and North America, but increasingly in all the settled portions of the globe. History provides examples of isolated cities with several hundred thousand people, usually commercial centers located in fertile agricultural areas, or administrative capitals supported by the wealth of such favored regions. A network of large cities, on the other hand, is based on the creation of an elaborate technology and involves the interchange of varied goods and services, not only between adjacent cities and their immediate hinterlands, but also among cities, regions, and nations that are widely scattered. Thus, in the 30 years from 1888 to 1918, the population of Japan’s six largest cities rose from under 2.5 million persons to over 6 million (Taeuber 1958, p. 47). Between 1947 and 1957, Singapore’s population grew by almost a quarter of a million people, representing an annual average growth rate of some 3 per cent. Such growth was supported not by any local natural resources but by the pre-eminence of Singapore as a trade center in its region.

The reasons for urban growth are complex, whether we are dealing with South Africa or northern Europe, Asia or the Americas. In terms of purely demographic variables, cities grow because of natural increase, net in-migration, or a combination of these. In terms of cultural variables, growth is dependent on technological developments in industry, transportation and communication, agriculture, science, and medicine. Such developments have reduced agricultural labor requirements, made possible the exploitation of distant as well as local resources, and established cities as the centers of perceived opportunities for migrants. They have made close living possible for masses of people by controlling epidemics and providing for the necessary transportation of persons, food, and goods.

Urban concentration

In the industrialized nations the pattern of population distribution now exhibits a high degree of concentration. Even in those agricultural countries that have not achieved full economic development, cities are claiming a rapidly increasing percentage of the total population. In Malaya, for example, the proportion of the population living in centers of 1,000 or more people increased from 35.1 per cent in 1947 to 50.5 per cent in 1957 (Caldwell 1963, p. 41). Indeed, since World War n, urban growth rates have tended to be highest in the less developed nations. In such countries rates of growth for smaller cities have commonly been higher than for the largest city, although absolute increments have remained highest for the major centers.

The increasing concentration of population in urban areas, however these are denned, is a worldwide phenomenon. But in general the more developed nations are also the most urbanized. For instance, in England and Wales fully 80 per cent of the population was denned as urban in 1961. Other countries with over 60 per cent of their populations in the urban category are, in descending order of per cent urban, Australia, Israel, Denmark, Sweden, East and West Germany, Scotland, Canada, the United States, Chile, New Zealand, Japan, Belgium, and Venezuela. By contrast, countries with under 25 per cent of their population in the urban category included, in the early 1960s, Ghana, Kenya, Senegal, the Sudan, Tanganyika, Togo, Cambodia, India, Indonesia, Pakistan, Thailand, and North Vietnam (percentages based on data compiled from official sources by the author; compare Demographic Yearbook 1962, Table 9, pp. 304–315).

The definition of urban population varies markedly from country to country and may shift over time. Nevertheless, by any definition, industrial growth has been closely tied to urban growth. A concentration of population in urban areas may also be found in countries like Denmark, where commercial agriculture is of prime importance. In addition, there are many developing countries, such as Thailand or Egypt, which have one or more cities growing at a more rapid rate than is commensurate with their increase in employment opportunities (a trend sometimes called “overurbanization”). It has been alleged that heavy net migration to such cities reflects the “push” of excess population off the land, but such a view fails to explain the long history of rural population pressure without migration. Proponents of this type of theory also tend to overlook the fact that marginal urban employment often represents a gain in the migrant’s level of living (Sovani 1964, pp. 117–119).

Number and size of centers

There is a noticeable difference among countries in the distribution of urban population by size of center. In India, for instance, there were, in 1951, 11 cities with populations over 500,000 and another 59 cities with populations between 100,000 and 500,000. Despite this, slightly less than 7 per cent of the country’s total population lived in cities of 100,000 or more, whereas nearly 17 per cent were dwellers in places (many of them agricultural villages) of 2,000 to 5,000 population. By contrast, in Australia there are only 6 centers containing more than 100,000 people, but in 1947 some 51 per cent of the total population could be counted in the large-urban category and only 8 per cent in the small-urban grouping (see Gibbs 1961, p. 405, Table 1). The total population in India’s “urban places” (that is, in all those centers of 2,000 or more people) was 24 times greater than that in places of comparable size in Australia. Obviously this is, to a considerable degree, a function of differences in the total numbers of inhabitants of the two countries– 441,631,000 in India in 1961 and 10,508,000 in Australia in the same year. What is significant is that the ratio of urban to rural population and, within the urban category, the ratio of residents in large centers to those in small ones are both totally different in the two countries, reflecting profound differences in the extent to which each is urbanized. This in turn suggests important national differences in economic and social organization.

Primate cities

Another way to denote degrees of urban concentration is to compare countries with respect to the percentage of either the total population or the total urban population that is found in the largest city. Great variability will be found from country to country. For instance, the more than 14,000,000 people in the New York metropolitan area in 1960 were still only 8 per cent of the total U.S. population of 179,323,175. But in Greece the 1961 population of 1,852,709 for metropolitan Athens constituted 22 per cent of the national population, and in Uruguay in 1963 the 1,173,114 inhabitants of Montevideo made up 46 per cent of the total population.

In many countries, particularly those of small or medium size, the urban population shows a pronounced concentration in a single center. Such places, termed “primate cities,” tend to mass within their limits not only population but also a variety of economic, social, and political functions. These diverse functions—commerce, government, manufacturing, recreation, and so on—are the basis of support for relatively large local populations. It is sometimes alleged that this concentration at one point in space inhibits the growth of rival cities and thus holds back national development by focusing the means of growth in a single limited area. This argument remains unproved and ignores the stimulus to development which is achieved by a concentration of growth factors. Moreover, primacy may be a temporary phenomenon since, although it is logical to suppose that the primate city bears some fairly stable size relation to the cities beneath it in rank, the assumption is not borne out by any available data. Estimates of the 1955 populations of the metropolitan areas in ten countries show the size of the largest urban area to vary from 1.1 times that of the next largest, in Canada and Italy, to 16.3 times in South Vietnam (California, University of…1959).

Ecological considerations

From the ecological viewpoint, an area constitutes an environment to which a collective adaptation has been made by a population. The pattern of distribution of human beings over an area is thus a generalized indication of their economic organization and life style [seeEcology, article onHuman Ecology]. It is also an index of the degree to which there have developed complex, welldifferentiated social orders, in which both activities and populations exhibit high degrees of specialization as interdependent unit parts of areally organized social structures. Such social orders, or communities, show relatively high rates of both migration and social mobility, subjects of considerable prominence in distribution research.

A central problem for ecology, then, is to understand the collective adaptation, to a particular environment, of an aggregate with identifiable characteristics. Among human beings such adaptation varies with the existing technology and results in distinctive and modifiable patterns of social organization. Functionally these human communities are affected by their position in a hierarchy of interdependent communities, ranked in size and distributed over space. The physical and social structure of the community may be viewed as responses to its predominant functions, whether that community be hypothetical or real [seeCity, article oncomparative urban structure]. However, the relationships among these factors—specifically those between numbers of people and their distribution in space—have not as yet been systematically explored. Current knowledge depends rather heavily on a combination of logical assumptions, conjecture, and limited, unrelated observations of particular populations that are often unrealistically treated as closed systems. Interdependence of parts is well established in theory, but quantitative proof is largely lacking (see, however, the demonstration of economic interrelations in Duncan et al. 1960).

Nevertheless, ecological studies continue to demonstrate how varying distributions are reflected in clearly differentiated patterns of organization. For example, Donald Bogue (1949, part in) has shown how variations in population density, related to distance from metropolitan cities, were associated with variations in the average amounts of trade, services, and manufacturing activities in the metropolitan communities of the United States in 1940. The growth of cities has been shown to be accompanied by an increasing differentiation of specialized parts, with a relative concentration of population and of functions in particular sectors. The location of functional areas and their relations to one another vary in time and space, but the tendency for an uneven distribution of people and activities to exist has led to the development of theories of urban structure based on zones, sectors, multiple nuclei, and functional differentiation (Duncan et al. 1960, chapter 2; Harris & Ullman 1945).

Ecological processes

The tendency toward uneven distribution has also led ecologists to emphasize such processes as concentration, centralization, segregation, invasion, and succession in order to describe aspects of the process of population redistribution in local areas. The study of the massing of people (concentration), particularly around points of specialized activity (centralization), or the tendency for people or activities of a similar sort to locate together and to develop areas of relative homogeneity (segregation) seems superficially to present few methodological difficulties. Closer examination, however, shows that these common concepts are difficult both to define and to measure. A major problem is that none of the processes is independent of area. Accordingly, the selection of different areal boundaries will alter the substantive findings. For instance, in calculating the population density of a city, it makes a great deal of difference whether the base for calculation is the central part of a metropolitan area or some larger unit that includes suburban or even agricultural land. Similarly, the various indexes that have been constructed to measure residential segregation have frequently been criticized for failing to measure what their authors thought they were measuring. The difficulty, again, is in the areal base unit selected.

Rank-size distribution of places

The question of distribution of population by rank-size of community has received considerable attention. As early as 1826 the German economist J. H. von Thiinen, in Der isolierte Staat, suggested that ideally a single city on uniformly flat land devoted to agricultural activity would locate centrally and become surrounded by concentric rings of land use. Over a century later Walter Christaller (1933) argued in a similar vein that a central place, whose function it is to provide services for a surrounding hinterland, can exist only where there is an amount of productive land sufficient to support it. The central-place theory is an idealtype formulation and therefore cannot be expected to provide an accurate description of the distribution of a specific population. Nevertheless, it is useful in identifying a number of factors involved in place distribution and in providing a generalized measure from which deviations are to be expected in reality. The explanations of such variance are not apt to be covered by any single theory. [SeeCentral Place.]

A number of attempts have been made to formulate a more precise statement of the distribution pattern of communities as a function of their size (Berry & Garrison 1958). One example is the work of George K. Zipf (1949), who developed a rule of rank-size relations to describe a general tendency toward rank frequency in all human activity. As applied to communities, Zipf’s hypothesis attempts to make specific the common observation that in most inhabited regions there are a few large places and an increasing number of smaller ones. The number of inhabitants of a center multiplied by its rank would thus yield a constant. Testing this simple rank-size rule with places of 1,000 or more population in the United States in 1950, O. D. Duncan and A. J. Reiss, Jr. (1956, pp. 26–28) concluded that it did not provide a good fit for the distribution of places by size in that year. Despite this they judged the rule in a generalized form a useful summary of the widely noted inverse relationship between the size of a community and the number of such centers. The same authors went on to demonstrate that there are significant differences in age, marital conditions, income, and other demographic and social factors by size of place. This confirms the importance of studies of the changing distribution of population into metropolitan, urban, and rural categories, supplemented as necessary by finer classifications.

Demographic Yearbook 1962. 14th ed. 1962 New York: United Nations. → Special topic: Survey and Statistics on Marriage, Divorce, Birth, Death and Life Expectancy. Prepared by the Statistical Office of the United Nations in collaboration with the Department of Social Affairs.

“Population growth” seems a partial term for a field of study where decline, fluctuations, and sharp changes can also occur, unless it is understood that “growth” is not necessarily positive or monotonic. Population growth is the sum of natural increase (births minus deaths) and net migration (immigrants minus emigrants); but each of these balances can be negative, and so can be their sum. Population growth equals natural increase only where net migration is nil or negligible.

Ordinarily, population growth is studied by the comparison of rates in time and space—for example, by comparing annual or average annual rates of growth. This presupposes the absence of compelling events disruptive of orderly time sequences, such as the invasion of a territory, removals or displacements of minorities, and casualties sustained in famine, epidemic, war, or a large natural disaster. Such events are said to cause population “gains” or “losses,” and balance sheets can be drawn up after their occurrence. But it is not possible to make a clear separation between population changes caused by disruptive events and all other kinds of population changes. In a long historical perspective, all societies are prone to incur crises; the victims, constituting “excess deaths” in the short run, are then part of the normal long-run risks of society. Again, war losses are not confined to deaths from deliberate military action but include excess deaths due to deterioration in food, shelter, and medical care, a birth deficit due to the mobilization, captivity, or death of potential fathers, etc. Such losses are, therefore, incalculable.

Population growth from 1950 to 1960

Two types of population growth rates are used: exponential rates (per 1,000 per annum), for comparison with other demographic measures, and compound interest rates (per cent per annum), for comparison with growth in nondemographic quantities, e.g., income. There is a slight difference in per-unit value of these rates, since the exponential rate refers to population of midyear, or the mean of the period, while the compound interest rate refers to that at the beginning of each year.

Table 1 shows world population counts and population growth rates, as compiled by United Nations demographers, for the period 1950–1960. Many of these figures are unofficial, and some are very rough. The four most populous countries contain half the world’s people within one-third of the world’s land. The 20 countries which follow have 30 per cent of the world’s inhabitants on one-sixth of the world’s land. The 205 less populated countries and territories, not separately shown, extend over large land areas, including Canada, Australia, and large portions of Africa and South America.

From 1950 to 1960 the world’s population increased by an amount (482 million) larger than the 1960 population of India (433 million) or of Europe outside the Soviet Union (425 million). The 1950–1960 gain in China alone approximately equaled the 1950 population of Japan; other comparisons of this sort are no less spectacular. Exceptionally high rates of growth were shown by Indonesia and by Pakistan, which by 1960 had both surpassed Japan in population. Comparisons between the growth rates of European and non-European nations are also instructive; Brazil, for instance, with a growth rate of 3 per cent per annum, not only is growing twice as fast as any of the western European nations except Switzerland but also has, since 1950, drawn far ahead of any of them in absolute numbers.

Among gains in average density not shown in the table, it should be noted that during 1950–1960 some 800 persons were added per square kilometer of land in Hong Kong and about 160 per square kilometer of habitable or cultivable land in

Table 1 – Estimated 1950 and 1960 population, land area, population gain 1950-1960, gain per square kilometer, and average annual rate of growth: 24 most populous countries and rest of the world

POPULATION Millions

LAND AREA

POPULATION GAIN

AVERAGE ANNUAL GROWTHa

1950 (midyear)

1960

Million square kilometers

Millions

Per square kilometer

Per cent

a. Compound interest rate.

b. Population estimates very rough.

c. The 1960 total of 99.95 millions was adjusted for underenumeration of the 1961 census as estimated by the Planning Commission’s report. No attempt was made to adjust the 1950 total. This probably accounts for the much higher rate of growth than the officially calculated one of 2.1 per cent per annum for 1950–1960.

d. 1955–1960 average: 2.8.

e. Habitable and cultivable area: 35,580 square kilometers.

f. Includes East Berlin.

g. Consists of 205 countries and territories,

h. Antarctic not included.

Sources: Adapted from United Nations 1966 (population); Demographic Yearbook 1965 (areas). Population gain and growth rates calculated by the author.

Egypt In Table 1 the density gain of South Korea stands out as the largest, and average density increased by more than 20 persons also in India, Japan, Pakistan, West Germany, and the Philippines. Some fast-growing countries (e.g., Brazil and Mexico) had smaller density gains than some slow-growing countries of initially high density (e.g., the United Kingdom and Italy). But the measure is summary and can easily deceive. Gains in average density have been slight in the United States and Argentina, while, with rapid metropolitanization, the proportion of those countries’ inhabitants living in high-density zones has markedly increased. Also, average density is unrepresentative of density in those minor portions of China, Indonesia, and Pakistan which contain the majority of those countries’ populations.

The countries in Table 1 can be grouped by 1950–1960 growth rates as follows: (1) 2.5 per cent or higher—Brazil, Nigeria, Mexico, Turkey, South Korea (based on 1955–1960 data only), Egypt, the Philippines, and Thailand, totaling 288 million inhabitants in I960; (2) 1.5 to 2.4 per centChina., India, the Soviet Union, the United States, Indonesia, Pakistan (based on 1950 and 1960 official estimates), Poland, Burma, and Argentina, totaling 1,745 million inhabitants in I960; (3) 0.5 to 1.4 per cent—Japan, West Germany, Italy, France, and Spain, totaling 272 million inhabitants in I960; and (4) 0.4 per cent or less—the United Kingdom and East Germany, totaling 70 million inhabitants in 1960.

The above list excludes the 205 less populated countries and territories, but it is evident that the great majority of the world’s population was subjected during 1950–1960 to rates of growth between 1.5 and 2.4 per cent per annum and that growth rates greater than 2.5 per cent were not exceptional. In these respects the 1950s have been unlike any earlier phase in mankind’s history. Except where there occurred settlement of mostly vacant territory, no sizable population has ever before grown at a rate as high as 2.5 per cent. Sustained growth of a large population at a rate as high as 1.5 per cent was relatively exceptional in the decades before 1950.

World population growth up to 1750

If the history of Homo sapiens is counted in hundreds of thousands of years, the present world population could have resulted from an initial small tribe with an annual rate of growth of 0.01 or 0.02 per cent. The notion that any human population would grow so steadily at so minimal a rate is, of course, absurd. Both growth and decline must have occurred at different epochs in different areas, but during some critical epochs growth may have prevailed significantly over decline. Thus, very few million individuals could have subsisted at any time on the earth’s surface with a paleolithic culture, whereas a neolithic technology and social organization might have sustained a substantial number of millions.

The major early metal-using civilizations (those of the Euphrates, Nile, Indus, and Yellow rivers) probably supported several million inhabitants each, all of them dangerously exposed to destructive predatory attack. Establishing large areas of comparative peace and security, the Han empire of China, Asoka’s empire in India, and Roman rule around the Mediterranean basin combined larger populations, between 50 and 100 million each (Durand I960; Russell 1958; Boak 1955). The world’s population at the beginning of the Christian era has been estimated at 300 million.

Undoubtedly there was population decline when these empires crumbled and more still when reliance on military prowess became a substitute for the then irrecoverable social organization that the empires had sustained. Previously sizable populations in Central America, Mesopotamia, and southeast Asia have also vanished at various times, possibly owing to similar cultural changes. But historical demographic research has been focused mainly upon Europe and China. According to J. C. Russell (1958), Europe’s population was 33 million in A.D. 1, had fallen to 18 million by about 600, rose to 70 million after the end of the thirteenth century, and was reduced by the Black Death to possibly little more than 40 million. John Durand (1960) has estimated that China’s population was 71 million in A.D. 2, had fallen to 37 million by 705, rose to more than 120 million in the thirteenth century, and was reduced to 60 million in the fourteenth. Inexplicably, these ups and downs in Europe and China were nearly synchronized. Little is known about population changes elsewhere in the world during the same centuries; if we had more knowledge of such changes, it might be guessed how much the world total had shrunk by the seventh century, how much it had risen by the thirteenth, and how much it decreased again in the fourteenth. These guesses cannot justifiably be made without a prior marshaling of large amounts of relevant evidence, most of it very hard to find.

As estimated by W. F. Willcox (1931) and revised by Alexander Carr-Saunders (1936), world population may have totaled 545 million by 1650, rising to 728 million by 1750; an average annual rate of world population growth of 0.3 per cent is thereby suggested, not impossible for that period or for times such as the rise of the ancient empires or a few of the centuries between A.D. 700 and 1300. Since growth did not occur in every area and probably met with temporary reversals even in the areas of growth, a long-term world average of 0.3 per cent can be consistent with rates two to five times as high within relatively favored areas in undisturbed times, and such rates would have resulted under premodern peacetime levels of fertility and mortality in organized states. Such a rate might have caused the 300 million population of Roman times to increase to the size of the present world population within one millennium instead of two. Actually, severe cutbacks occurred in the first few centuries A.D. and again in the fourteenth century.

Growth in world regions, 1750–1960

Tables 2 and 3 link the world population estimates of Carr-Saunders (1936), used here for 1750–1900, with more-recent estimates, for 1920–1960 (United Nations 1966). Comparable data for 1910 are lacking, but rough figures can be inserted, since the two series are in substantial agreement. The figures are for the traditional continents; hence, Europe includes the Soviet Union up to the Ural Mountains.

It will be seen that, by half centuries, world

Table 2 – Estimates of world population (In millions), for selected periods, 1750–1960

Asiae

Europea

Africa

North Americab

Latin Americac

Oceaniad

World total

a. Includes portions of Soviet Union and Turkey, as traditionally assigned to Asia and Europe respectively.

population growth accelerated gradually until the late nineteenth century and sharply thereafter. This happened despite a nineteenth-century slowdown in Asia (particularly China) and a twentiethcentury slowdown in Europe. Africa’s population probably languished under the slave raids until pacification caused its renewed growth. The small indigenous populations of North America and Oceania were swamped by European settlers, who arrived at a high rate in relation to initially small numbers; but the growth rates of these two continents decreased as the settlement populations themselves attained larger size. In Latin America an initially substantial indigenous population is believed to have declined severely after the Spanish conquest; the partly mixed population eventually resumed growth, and its present rate of natural increase is of a level unsurpassed by any other population of such size.

If we examine the same data by decades, it becomes clear that the world’s population was, at the turn of the century, already growing at the rate it almost maintained until 1950–in spite of a number of setbacks: World War i and a worldwide influenza epidemic in the decade from 1910 to 1920; the economic depression of the 1930s; and World War ii in the 1940s. Accordingly, an unprecedentedly high rate of growth emerged in the relatively undisturbed 1950s. Europe (including most of the Soviet Union) suffered the heaviest war losses and fell increasingly behind the world average rates of growth, although even here growth

Table 3 – Average annual rates of world population growth (per cent), for selected periods, 1750–1960

Asiae

Europea

Africa

North Americab

Latin Americac

Oceaniad

World total

a. Includes portions of Soviet Union and Turkey, as traditionally assigned to Asia and Europe respectively.

was faster in the 1950s than in any decade since 1910. The manner in which Africa’s population growth has accelerated is guesswork, but there is no doubt that the current rate is high. Immigration has been of decreasing effect in the Americas and in Oceania. A large recovery from the depressed birth rates of the 1930s brought population growth in North America and Oceania back to a high level in the 1950s. Because of decreasing death rates, the rate of natural increase has risen enormously in Latin America, very considerably in Asia, and at least appreciably in Africa.

Projections and forecasts

Methodological considerations

The dynamics of population growth has come to be recognized as a complex subject and far from self-contained. On the scale of decades, potentials for growth depend on the age composition of the population. But changes in age composition occur also as a result of changes in the components of growth: principally, changes in the birth rate; to a minor extent, relative changes in age-specific death risks and also migration, in those instances where this is large and affects particular age groups. Although the crude birth rates and crude death rates roughly reflect fertility and mortality trends, both they and the consequent natural increase are in part a function of varying age composition and should be interpreted accordingly.

A fall (or rise) in mortality affects population growth very directly, especially in high-fertility populations which have age structures such that any considerable change in death risks causes a large change in the crude death rate. The present rapid accelerations of population growth in Africa, Asia, and Latin America are thereby explained.

A change in fertility does not attain its full effect on population growth until the passing of several decades. The effect on the birth rate becomes large when the reduced (or increased) numbers of children reach the ages of parenthood. In the still longer run, the proportions of persons of advanced age can become considerably altered, thereby affecting the level of the crude death rate. The higher proportion of aged persons explains why there are higher death rates in European countries with superior health conditions than in some poorer countries elsewhere.

These few observations do not exhaust the analytic complexity of the subject. It must be added that the fertility, mortality, and migration changes themselves occur in response to changing economic and social conditions, attitudes, and culture.

The future of world population

A population projection (or forecast) is calculated, age group by age group, by applying data and trends in agespecific fertility and mortality rates to an initial set of data or estimates of the population’s age composition. The quality of the basic data is, of course, important and may require detailed analytic appraisal or the construction of estimates corrected for detectable sources of error. Judgment is necessary, furthermore, concerning factors likely to affect levels and trends in fertility, mortality, and migration in the future and concerning the likely nature and extent of those effects. An area of plausible foresight may then become circumscribed that, if sufficiently narrow, can provide a basis for economic and social decision making. Since plausibility of the moment is sensitive to any new item of information, projections intended to have predictive relevance may have to be revised frequently.

Tables 4 and 5 show calculations of future world population, as prepared by the United Nations (1966). The distinction here between “projection” and “forecast” lies in the intended greater predictive relevance of the latter. A projection may show the consequences of given trends, whether these are believed likely or not. The consequences of trends or changes judged to be likely constitute a forecast.

The “constant fertility, no migration” projection shown in Tables 4 and 5 measures the long-range effect of continuance of world-wide population trends which were typical of the 1950s: a continuing tempo in the decline of mortality, maintenance of current levels of fertility, and no migration. The effects of such trends, calculated separately for each region, are then summarized. On these assumptions, population growth in most regions would accelerate much beyond the 1950–1960 rate and the world’s population would total 7,500 million by the century’s end.

Table 4 – Projections and forecasts of world population (in millions), 1960–2000

The forecasts employ varied assumptions, made separately for each region, as to plausible decreases in mortality, some continuance of recent currents of migration, and the possibility that sooner or later substantial decreases in fertility might appear in different parts of the world. Three sets of forecasts were originally calculated: two aiming near the upper and lower margins of probability, and the “medium” set near the center of the range of what present information suggests to be fairly probable. Only the medium forecasts are shown here. The information available at the time the calculations were made suggested as most probable a continuance of world population growth at approximately its recent rate for at least three and possibly several more decades, this being a net outcome of probable acceleration in some regions and slowdown in some others. For the year 2000 the medium forecast leads to a world total of about 6,000 million; the high, to 7,000 million; and the low, to 5,400 million.

It is evident that many decades will have to elapse before ordinary processes can reduce the current tempo of world population growth to a moderate rate. The intervening phase of rapid growth adds human numbers so large as to be difficult to imagine. One may justly wonder whether human ingenuity will suffice either for a sufficiently rapid strengthening of social organization to cope with the increasing tasks or for a sufficiently rapid spread of motivation for and confidence in methods of family limitation throughout the world.

United Nations, Department of Economic and SocialAffairs 1958 The Future Growth of World Population. Population Studies, No. 28. New York: United Nations.

United Nations, Department of Economic and SocialAffairs 1966 World Population Prospects as Assessed in 1963. Population Studies, No. 41. New York: United Nations.

United Nations, Department of Social Affairs, Popu-Lation Division 1953 The Determinants and Consequences of Population Trends: A Summary of the Findings of Studies on the Relationship Between Population Changes and Economic and Social Conditions. Population Studies, No. 17. New York: United Nations.

United Nations, Department of Social Affairs, Popu-Lation Division 1956 Manuals on Methods of Estimating Population: 3. Methods for Population Projections by Sex and Age. Population Studies, No. 25. New York: United Nations.

Willcox, Walter F. 1931 Increase in the Population of the Earth and of the Continents Since 1650. Volume 2, pages 33–82 in National Bureau of Economic Research, International Migrations. New York: The Bureau.

Population policies may be defined as legislative measures, administrative programs, and other governmental action intended to alter or modify existing population trends in the interest of national survival and welfare. Many aspects of public policy and of social change in general have an impact upon demographic trends. Population policy embraces those aspects of public policy that are designed to counteract the unwanted demographic effects of over-all policy and of other social forces. Most frequently, attention is focused upon efforts to maintain, increase, or restrain the rate of growth of a population. Thus, the major purpose is to control population size, but consideration may also be given to influencing its composition and its geographic distribution.

The quantitative aim of population policy is emphasized here, partly because policies now in force are concerned primarily with affecting size and rate of change and partly because the inclusion of nonquantitative, or qualitative, aims would make population policy virtually synonymous with public policy in general. Biological quality, which is the object of measures designed to control the genetic structure of a population, is sometimes regarded as properly the concern of population policy. Although some countries have enacted legislation that authorizes abortion and sterilization on eugenic grounds, the number of such operations is quite small and their effect upon the biological constitution of the population as a whole is probably negligible. Differential fertility, on the other hand, may have some effect, but existing policies do not attempt to control that aspect of demographic change. Current action in this area is largely confined to those sections of immigration policy that are selective as to racial or ethnic origin.

Historical background

Government concern over matters of population is not a new phenomenon. State intervention, in the form of laws or decrees encouraging marriage, taxing the unmarried, subsidizing families with children, regulating immigration and emigration, fixing a legal minimum age for marriage, and the like, have existed since ancient times (Glass 1940, chapter 2). In general these measures represented a populationist philosophy that equated power and prosperity with large numbers.

The expansionist motivation in population policy reached a climax in Germany, Italy, and Japan during the period between the two world wars. Intensive pronatalist propaganda, cash payments to families with children, the rewarding and honoring of motherhood, the repression of birth control, the regulation of emigration, and the enactment of “eugenic” laws, all reflected the drive for larger native and racially “pure” populations, and they were directly associated with the political and territorial ambitions of the Axis powers.

During the same period, policies with a somewhat similar content but a different rationale were taking shape in other countries where very low rates of growth were evoking fears of an impending decline in numbers. Fertility rates were below replacement levels in many of these countries, and although only France and Austria actually recorded an excess of deaths over births, it was considered but a matter of time until most of western Europe would be experiencing a natural decrease of population. At the same time, sustained economic depression was precipitating a new concept of social justice, and governments were taking steps to protect workers against the risks of unemployment and to guarantee a minimum family wage that would take account of the number of dependents supported by each worker.

Although it was not clear to what extent the low birth rates then current were a continuation of the secular trend and to what extent they were a temporary phenomenon, it was thought that low marriage rates and low fertility within marriage had an essentially economic explanation. Consequently, the attempt to sustain or increase the birth rate became linked to the development of social security programs, particularly those aspects of social security that contribute to the economic security of the family. Because of this linkage, it is sometimes difficult to say whether measures favoring the family, maternity, and infancy have a demographic as well as a welfare intent, unless the government concerned specifically so states. Insofar as these programs do have a demographic intent, they are distinguishable from the populationist policies described above, in that they are not expansionist in the imperialist sense but, rather, are animated by a desire to avoid population decline or, at most, to achieve a gently increasing population.

Similar programs have developed in the Soviet Union and eastern Europe, as an integral part of the plan to build the socialist state. The populationist overtones of these programs stem in part from the old controversy between Malthus and Marx, in which Marx took the position that “overpopulation” was a misnomer for imperfect social organization, and in part from a felt need, in the Soviet Union at least, for a larger population. But in these countries, as elsewhere, the nature of population policy—and even the question of whether a policy exists—is to some extent a matter of the interpretation a government chooses to make of its actions and programs. Thus, a nation’s stated policy is not necessarily an exact statement of its purposes of the moment. Indeed, the prevailing pattern of social and political organization is such that much of national policy in any area takes form through a series of compromises between contending pressures and hence has elements of ambiguity, not to say of ambivalence.

After World War II, with the emergence of new nations and a growing awareness of the economic problems of underdeveloped countries, population policies that represented a different point of view began to develop. In many of the underdeveloped countries mortality was falling rapidly, as a result of large-scale preventive measures, but fertility remained high and rates of increase as great as 2.5 to 3.0 per cent per annum were either recorded or in prospect. Such rates were without precedent in Western experience. They implied a possible doubling of population within a generation and aroused fears that the effort to raise levels of living would be impeded by the necessity to provide subsistence for the increasing numbers. Policies that favor reducing or stabilizing the rate of population growth have therefore begun to evolve in some of the densely populated underdeveloped countries of the Far East and the Caribbean.

Elements of policy

Ideally, population policy involves the examination of past and current demographic trends and their causes; an appraisal of the future demographic changes implied by these trends; an evaluation of the social and economic consequences of expected patterns of change, in the perspective of what is regarded as the national interest; and finally, the adoption of measures designed to bring about desired changes or prevent undesired ones. Demographic trends are a function of changing relations between the forces of fertility, mortality, and migration, whether in the population as a whole or differentially in its various segments. Policy makers are therefore logically concerned with understanding the factors of change in these three processes and with ways and means of influencing the direction and amount of change in each of them. However, practical considerations are such that most of population policy, as it exists today, is directed at influencing fertility, although the trends and effects of migration and mortality may also be carefully studied, for changes in them can be the precipitating factors that render population a “problem.”

Migration

Control of international migration as a means of adjustment between high-density countries and low-density countries holds only limited possibilities, principally because of national feelings, political differences, ethnic preferences, problems of assimilation, and fears of the economic consequences of inundation from abroad. The immigration laws of the so-called countries of immigration (Australia, New Zealand, and most of the countries of western Europe and the Americas) are generally restrictive, setting limitations upon the number and source of immigrants and barring those who, for political, social, or medical reasons, are considered undesirable (International Labor Office 1954). Although some migration from highdensity to low-density countries is encouraged, it is carefully controlled, often through bilateral agreements between the governments concerned. In these programs quantitative aims are present, but nonquantitative considerations usually take precedence.

From the point of view of the densely populated underdeveloped countries, there are, thus, no available outlets that could possibly siphon off the current and prospective increases in numbers. In effect, the solution of what are regarded as demographic problems is almost strictly a national affair. Adjustments of population to resources or to a program of economic development must be effected principally within national borders.

Insofar as the redistribution of population is a demographic process, the regulation of internal migration may be regarded as population policy. This aspect of public policy has not, on the whole, been so regarded, its aims being generally qualitative rather than quantitative; but government action in this area can have great significance and can benefit from demographic analysis and demographic insights. The important internal migrations of the past have, like other demographic processes, been largely unplanned and unguided; chief among them has been the movement from farm to city. Problems of urban congestion and of urban and rural slums exist almost everywhere. Modern programs of resettlement, city planning, urban renewal, relocation of industry, and aid to agriculture are examples of government attempts to cope with such conditions, and some of them utilize a demographic approach and have in mind a partially demographic solution—namely, to influence the redistribution of population. This facet of policy could be increasingly emphasized if social and economic planning should become more prevalent and more sophisticated; it would take on a quantitative character if security considerations were to become a compelling factor. In the underdeveloped countries economic progress will depend in part on the success with which population distribution and redistribution are taken into account and made to contribute to, rather than impede, development.

Mortality

Broadly defined, population policy includes measures intended to affect the death rate. But the purpose of such measures is to improve the health of the population, not to control the rate or direction of numerical change. To include the totality of such measures would be equivalent to identifying health policy with population policy. Manipulation of the death rate in order to control the rate of growth is not feasible, because there is only one policy in relation to mortality that is socially acceptable—namely, to reduce it. In industrial countries where there is a desire to encourage population growth, death rates are already so low that there is very little to be gained, in the way of growth, from further reductions at most ages. Thus, population policy, as such, does not place a great deal of emphasis on the reduction of mortality, although, of course, other aspects of welfare policy do emphasize it very strongly. Indeed, the concept of public health has been extended in most of these countries, by means of national health insurance schemes or national health service systems, to include individual medical care in the realm of public responsibility.

In the underdeveloped countries where there is a desire to restrict the rate of growth, it might be possible to relax the struggle against mortality and allow death rates to rise. However, such a policy not only is offensive from the humanitarian point of view but would also run the risk of defeating the basic objective of improving the living conditions of the general population. Governments that allowed death rates to rise would soon realize that a competent labor force, essential to economic development, cannot be achieved without some safeguards to health and some positive measures to insure adequate diet and tolerable working conditions. Furthermore, skills require training, practice, and education of some sort. Meeting these requirements would contribute to a fall in the death rate, even if the government, as a matter of population policy, took no positive steps to reduce mortality. And there is the added circumstance that, because of modern technical knowledge and facilities, the basic preventive measures necessary to control the spread of infectious disease–mass inoculation, spraying, and elementary sanitation– are relatively inexpensive and easy to administer.

Control of fertility

Under present political, cultural, and technological circumstances, the principal focus of efforts to influence population trends necessarily centers on the control of fertility. It so happens that, in general, countries wishing to stimulate growth are low-fertility countries and countries wishing to restrain growth are high-fertility countries.

Only three countries can be said to have coherent, carefully constructed, and frankly stated population policies: France, representing a strong pronatalist view; Sweden, representing a more tempered pronatalist view; and India, representing an antinatalist view. A much larger number of countries have taken cognizance of population problems in one way or another: by appointing commissions to study the question and make proposals; by issuing statements of official attitudes; or by enacting legislation which probably has inherent demographic aims, although other objectives may be the only ones acknowledged. A brief description of the policies of France, Sweden, and India, along with some indication of similar or relevant specific measures taken in other countries, should give perspective on how developments in this area are moving in the world in general.

France

The essentials of French population policy are set out in the Code de la Famille, which came into force in 1940 (“Decret relatif á la famille …” 1939). Its purpose is both to encourage family formation and childbearing in numbers sufficient to maintain a moderate increase in population and to counteract the general aging of the population. Specific provisions to this end include, on the one hand, positive measures for financial aid to marriage and child rearing and, on the other hand, repressive measures restricting the use of induced abortion and contraception. Subsequent legislation has introduced some changes in the program, the general effect of which has been to improve its administration and increase its benefits.

The principal economic measure is the system of family allowances. Monthly cash allowances are payable to all families having two or more children under 15 years of age; in special circumstances the age limit is as high as 20 years. Reflecting pronatalist intent, allowances are higher for the third and subsequent children than for the second child. Furthermore, families with only one wage earner receive allowances beginning with the first child, and the allowance per child is higher. In addition, prenatal and maternity allowances are available to all women. The amount of allowances is based on the current minimum wage of metalworkers, and so it tends to vary with the cost of living. As of 1960, three-child single-wage families received allowances equal to at least 133 per cent of the base wage. The prenatal allowance averaged 21 per cent of the base wage, and the maternity allowance, payable after the birth, was equal to 200 per cent of the base wage for the first birth and 133 per cent for subsequent births occurring within three years of a prior birth.

Further benefits to married couples include government loans for various purposes, tax reductions, and rebates on the costs of public services. Social services in aid of the family have taken the form of subsidies to school canteens, boarding schools, vacation camps, day nurseries, and kindergartens; the provision of household help; and family counseling. Certain benefits, available to persons covered by the social security scheme and contingent upon attachment to the labor force, are regarded as part of France’s program to compensate family expenses and have been regularly included in the computation of the costs of France’s population policy. Principal among these benefits are reimbursement for most of the cost of the medical care of the spouse and children of the insured, including maternity care of insured women and spouses of insured men, paid maternity leave for insured women, and leave with pay for the father at the time of the birth of a child.

On the repressive side, the Code de la Famille re-embodied earlier legislation which made birth control propaganda, sale or advertisement of contraceptives, and incitement to abortion illegal. The condom, considered a prophylactic, may be freely bought and sold, but other devices are forbidden. [For the laws governing abortion in France and other countries, see Fertility control.]

Supplementing the pronatalist policy is the encouragement of immigration of a type that is considered compatible with both manpower and demographic needs. A final aspect of French policy is the existence of the Institut National d’études Demographiques, created in 1945 to conduct research in problems relevant to population, follow studies and developments in other countries, and explore all possible means of increasing the number and improving the quality of the population.

Sweden

Demographically, Sweden is similar to France and most of the other countries of western Europe. Like France, Sweden has a closely reasoned, highly developed population policy that is oriented toward sustaining the birth rate. But in Swedish policy, consideration of individual welfare and personal freedom have taken precedence over pronatalist aims wherever the two were in conflict. Also, much more emphasis is placed on payments in kind and on the provision of institutional or social services in behalf of the family.

Government action in matters of population began in 1935, with the appointment of a population commission. On the basis of the deliberations and recommendations of that commission and of a second commission, which functioned from 1941 to 1946, Sweden has developed a well-coordinated program, the themes of which are voluntary parenthood and child welfare (Myrdal 1941; Gille 1948). Family allowances are payable in behalf of each child under the age of 16. Reflecting a welfare, rather than a pronatalist, emphasis, this is a flatrate allowance beginning with the first child, and the rate per child does not increase with the number of eligible children. The amount relative to the cost of child care is somewhat lower than that paid in France, but the system of supplementary services and allowances in kind is much more exhaustive. The supplementary aids include marriage loans for the purchase of household equipment, a comprehensive system of maternal and child welfare centers, housing and fuel grants for families of moderate means with two or more children, free school meals, home-help services, holiday travel for mothers and children of families in difficult circumstances, and tax relief. The sickness and maternity insurance scheme covers all resident citizens and registered aliens. Maternity leave is compulsory, and the costs of confinement are borne by the state. Women employees may not be dismissed because of pregnancy or childbirth.

In keeping with the aim of voluntary parenthood, contraceptive advice is given at hospitals and health centers, contraceptives may be purchased at all pharmacies, the laws against induced abortion have been relaxed, and sex education has been made a regular part of the school curriculum. The object of this part of the program is to improve the quality of the population, as well as influence population growth in the direction desired. Abortion has been legalized to the degree that medical boards may authorize the interruption of pregnancy on rather broadly defined therapeutic or eugenic grounds, taking into account the general social, medical, and psychological circumstances of the woman involved. Sterilization may be authorized for similar reasons. It was hoped that the more lenient attitude toward induced abortion would in the end reduce the number of such abortions; however, it is not yet possible to ascertain whether this program has had the desired effect (Gille 1955).

India

In India, population policy is oriented toward restraining the rate of increase, on behalf of economic development and of raising the level of living of the people. This policy was initiated in 1952, with the first five-year plan, and subsequent action has put increasing emphasis upon the need to reduce the widening gap between a lowering death rate and a persistently high birth rate. The third five-year plan, promulgated in 1961, stated, “The objective of stabilising the growth of population over a reasonable period must be at the very centre of planned development” (India 1961, p 675). The plan calls for a large-scale program of education and motivation for family planning, provision of birth control advice and contraceptive supplies, and government-sponsored research in demographic trends, contraceptive methods, and family-planning motivation. Family-planning clinics have been established in a large number of rural areas, and family-planning services are available at urban medical and health centers. [SeeCommunity, article oncommunity development.]

These activities are steadily expanding, with the government subsidizing the manufacture and distribution of contraceptives. The question of how to make the program more effective is under constant study. At the request of the government, the United Nations sent a team of experts to India in 1965, “to assess the problems involved in accelerating the adoption of family planning by the people and to advise the Government on action that might be taken for this purpose” (United Nations 1965, pp. 9–10).

The law against induced abortion has not been relaxed, and pregnancy may be artificially terminated only to save the life of the mother. Voluntary sterilization, however, is regarded as an acceptable means of preventing births, and the practice seems to be spreading. Another facet of Indian policy has to do with the effort to raise the average age at marriage. In this connection, the third five-year plan places special emphasis on the education of women and on the provision of new employment opportunities for women.

Programs in other countries

In Europe all the rest of the countries have adopted programs that resemble those of France or Sweden in various ways and to varying degrees, but in none of them has population policy been as fully developed or as clearly stated. These countries have family allowance schemes and social insurance or national health service systems that cover all or part of the costs of maternity and the medical care of workers and their dependents.

Measures in the Roman Catholic countries of western and central Europe and in the Netherlands are similar to those in France but less intensive. They may be characterized as favoring natality and as repressing the practices of birth control and abortion. Family allowances are generally of the progressive type; laws regarding birth control propaganda and the sale of contraceptives tend to be restrictive; induced abortion is prohibited. Although pronatalist influences contributed to the enactment of these measures, they do not necessarily have an announced or a sustained pronatalist intent. Two countries—Italy and the Netherlands —have been encouraging emigration.

Programs in the Scandinavian countries, the United Kingdom, and Finland are similar to those of Sweden. The general attitude is pronatalist, but demographic considerations take second place to considerations of immediate welfare. Family allowances tend to be of the flat-rate type; supplementary aids to the family and institutional services are provided; legislation regarding birth control is permissive. Supplementary aids to the family are especially well developed in the United Kingdom, where the population question was studied in depth by a royal commission and where the program has had the benefit of the commission’s findings and proposals (Great Britain 1949). In the attempt to combat induced abortion, legal strictures against abortion have been relaxed in Denmark, Finland, and Iceland; abortion and sterilization are permitted on medical, social, or eugenic grounds; and family planning is actively encouraged. In Norway only medical and eugenic grounds for abortion are recognized; in the United Kingdom, only medical grounds. Measures in the overseas Commonwealth countries of Canada, Australia, and New Zealand resemble those of the United Kingdom. In addition, these three countries have, since World War II, instituted policies promoting immigration of a selective type.

Policies in the Soviet Union and in eastern Europe since World War II have been pronatalist in tone. Family allowances of the progressive type predominate, and special awards for mothers of large families are a persistent feature. Since 1955, legislation against abortion has been greatly liberalized in most of these countries; in some the operation is obtainable at the woman’s request. The change was made on humanitarian and health grounds and was declared a measure intended to combat the dangers and frequency of induced abortion. The use of contraception, rather than abortion, is strongly advocated. The new policy does not necessarily indicate abandonment of the antiMalthusian point of view, but there have been some expressions of the opinion that rapid population increase may interfere with economic development (Mauldin 1960, p. 197; Brackett & Huyck 1962).

Outside of Europe, the Soviet Union, and the Commonwealth countries mentioned, nationwide family allowance schemes, inclusive health insurance or health service systems, and related measures in favor of the family have not yet developed very far, but programs of limited scope or of an extragovernmental type have begun to grow up in many countries (U.S. Social Security Administration 1961). The European type of program may be seen as a culture trait that is being diffused to all parts of the world. As such, it has no doubt acquired an aura of Tightness that makes it virtually independent of population policy. Changes of policy from pronatalism to antinatalism or indifference are, therefore, unlikely to dislodge it, although they may bring about some alteration of specific provisions.

Policies resembling that of India are emerging in a number of other densely populated underdeveloped countries. Intensive government-sponsored programs to promote family planning have been launched in Pakistan and the Republic of Korea. In Taiwan the government gives informal support to a program that is conducted by private organizations. The first five-year plan of Turkey reversed prior policy and provides for family-planning education. Iran’s third plan mentions the need to popularize family planning. In Tunisia a policy favoring birth control is under study and a family-planning campaign has been started. In the United Arab Republic the charter promulgated by the president in 1962 stated that family planning was one way of alleviating the problem of low per capita production. Official interest has also been demonstrated, by government approval or support of planned parenthood programs, in Hong Kong, Malaysia, Thailand, Barbados, Ceylon, and the Philippines. China has liberalized its laws on abortion and sterilization and, despite strong commitment to anti-Malthusianism, has begun to encourage birth control and advocate late marriage (United Nations 1964; Nortman 1964; Tien 1963; Studies in Family Planning).

Effects of population policy

Not much can be said about the effects of population policy. As far as the three countries with well-defined policies—France, Sweden, and India— are concerned, evidence that the desired effects are being produced is inconclusive. In France fertility is above prewar levels, and French analysts believe that French policy accounts for that fact. In Sweden, however, the crude birth rate of 1960 was the lowest in Europe and probably the lowest in the world. Growth rates remain high in India. Elsewhere current levels and recent trends in national birth rates appear to bear no consistent relation to the presence, purpose, or content of national policy.

It seems clear that once the majority of a population has recognized at the personal level the desirability of controlling family size, it will act without much regard for the position of the law or official policy. Thus, the secular fall in Western fertility took place over a period when birth control was officially opposed and policy, if any, favored increase. The experience in Japan since World War II is another case in point. Japanese law on abortion and sterilization was liberalized between 1948 and 1954, and at the same time the use of contraception, rather than abortion, was urged upon the population. Recorded abortions increased rapidly and soon were approaching the number of live births. By 1960 the birth rate had fallen to a level comparable with that in Western industrial countries. But the resort to abortion and the fall in the birth rate began before 1948; the practice had undoubtedly existed on a wide scale for some time (Taeuber 1958, p. 278). Legalization may have caused some of the increase in the number of abortions, but the important fact, from the sociological point of view, is that a great many people wanted to limit the size of their families. In other words, when such a conviction has arrived, ways and means of attainment will be found. An antinatalist policy has the problem of instilling that conviction; a pronatalist policy, of dispelling it. The question of whether governments can or will provide incentives strong enough to change behavior in this area is still open.

The period of the 1960s was one of rapid development in the area of population policy, especially among underdeveloped countries. Many influences —social, political, economic, religious—were at work, both in and outside of government and at both national and international levels. For instance, the U.S. Congress, in passing the 1966 Food for Freedom bill, specifically authorized the president to use the local currencies acquired in sales of food under the Food for Freedom program to set up birth control clinics in any nation covered by the program, if its government so requested. In January 1967 President Johnson, in his State of the Union message, formally endorsed the “export” of birth control as a continuing policy. The elements of a domestic population policy also began to emerge, with the deepening involvement of the U.S. Department of Health, Education and Welfare in birth control activities, and the support of these activities by certain members of the Congress (see U.S. Congress 1966). But the Roman Catholic church, in spite of mounting internal criticism and considerable evidence that many Catholics either were using or wished to use some form of “artificial” contraception, still had not modified its traditional stand by mid-1967. In the meantime, most governments of Latin America—the region with the world’s highest rate of population growth—had yet to evolve population policies, although privately sponsored conferences in 1965 and 1967 allowed, for the first time, some public expression of concern. During the same period, other governments, such as that of the United Arab Republic, whose natural resources seemed inadequate to support their rates of population growth, were undertaking extensive birth control programs for the first time.

But it was impossible to foresee the net impact of these forces upon the content and effectiveness of official policy in matters of population. A contemporary survey of government opinion, covering 53 countries in various stages of economic development, found that while many governments were aware of problems associated with population changes, there were differences between them in the interpretations they gave to such changes and in the policies they considered acceptable for dealing with the problems that are created (United Nations 1964). It must be concluded that knowledge about the interaction between population trends and economic growth is still imperfect and that there is plenty of room for honest disagreement about which population policies will be most effective in securing the general welfare.

For the latest information about population policies, the reader should consult the publications of the Population Council and of Planned Parenthood-World Population, both private nonprofit organizations located in New York City. The New York Times Index is also a useful reference source in this field.

Tien, H. Yuan 1965 Sterilization, Oral Contraception, and Population Control in China. Population Studies 18:215–235.

United Nations, Economic and Social Council 1964 Inquiry Among Governments on Problems Resulting From the Interaction of Economic Development and Population Changes. Report of the Secretary General, E/3895/Rev. 1. New York: United Nations.

United Nations, Economic and social Council, Population Commission 1965 Regional Demographic Activities. Report by the Secretary General, E/CN.9/192. New York: United Nations.

U.S. Congress, Senate, Committee On Labor and Public welfare 1966 Family Planning Program. Hearing Before the Subcommittee on Employment, Manpower, and Poverty, 89th Congress, 2d Session, on S. 2993. Washington: Government Printing Office.

U.S. Social Security Administration, Division of Program Research 1961 Social Security Programs Throughout the World: 1961. Washington: Government Printing Office.

Watson, Cicely 1952a Birth Control and Abortion in France Since 1939. Population Studies 5:261–286.

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Population

New Dictionary of the History of Ideas
COPYRIGHT 2005 The Gale Group, Inc.

POPULATION.

Perceptions of the meaning, implications, and control of reproduction and sexuality, at both the individual and community levels, are among the most important, but also the most challenging, in the history of ideas. Changes in human population helped shape the twentieth century and are creating new tensions in the twenty-first, but, despite the profound significance of childbearing to individuals and the impact of population change on economics, politics, maternal and infant health, the environment, and national security, the intellectual history of population is oddly fractured and frequently uninformative. There are still divisions on the exact mix of factors, such as vaccination and socioeconomic change, driving the dramatic fall in death rates that pushed the global population from 1,650 million in 1900 to 6,071 million in 2000, and there is no consensus on the factors driving falling birth rates in recent decades. Many societies have made pragmatic decisions about their citizens' access to modern contraception and safe abortion, but bitter and painful differences on ethics persist. The two most important shifts in the intellectual history of population—the Papal encyclical Humanae vitae and the Chinese "one-child" policy—represent diametrically opposed responses to population change.

An understanding of population must draw on reproductive biology, anthropology, economics, political science, and demography, as well as knowledge of cultural and religious beliefs, but cross-disciplinary progress has been slow. As Charles Darwin (1809–1882) acknowledged, Thomas Robert Malthus's (1766–1834) An Essay on the Principle of Population, published in 1798, was the intellectual trigger for The Origin of Species (1851). In the second half of the twentieth century, biological perspectives began to influence ideas about population change. Anthropologists reconstructed the demographic history of preliterate communities, which have been characteristic of the hunter-gatherer way of life for more than 95 percent of the time Homo sapiens has been a distinct species. In such societies, women sometimes do not menstruate until they are eighteen or even twenty years old, and pregnancies are well spaced by natural endocrine changes associated with breast-feeding. The average woman has six to eight pregnancies, half of which usually die, with the consequence that hunter-gatherer populations grow slowly.

The second half of the twentieth century saw unprecedented and unrepeatable changes in the growth of the global population. Rising potential fertility, as a result of changes in breast-feeding and the age of puberty, together with a rapid fall in death rates, pushed population growth rates up. The highest absolute growth in global population occurred in the mid-1980s, with more than 85 million more births than deaths per annum. During the same period, developed countries finally gained wide access to contraception and safe abortion, and in some regions average family size fell below two. In parts of Asia, which formerly had large families, the birth rate also fell to replacement level or below, although elsewhere in Asia and in Africa birth rates remain high. The implications for the health of women and children, for economic prosperity, social stability, and the environment of these changes are profound, yet some of the most important population changes were not predicted by most demographers.

The standard theory of the demographic transition was that a fall in the birth rate would lag behind any decline in the death rate and that birth and death rates would slowly stabilize as couples grew richer, became more educated, and made a rational decision to have smaller families. Frank Notestein, the distinguished American demographer, gave articulate expression to the theory. As the volume of empirical data on family planning has increased, so demographers have defined the proximal determinants of family size with increasing accuracy. These are the age at commencing intercourse, the prevalence of pathological causes of infertility, the suppression of ovulation associated with lactation, and use of contraception and abortion. However, the more distal determinants that make birth rates decline continue to be debated. The Office of Population Research at Princeton University explored the history of fertility decline in various parts of Europe and found that ideas about family planning spread by diffusion in homogeneous political and religious groups.

Clash of Ideas

The United States led the way in research that produced oral contraceptives and a new generation of intrauterine devices (IUDs) in the 1960s, although restrictive contraceptive laws remained in place in many states until the 1965 Supreme Court case Griswald v. Connecticut.Eastern Europe and parts of Scandinavia reformed their abortion laws in the 1960s and England followed in 1967. In 1972 the U.S. Supreme Court struck down state laws forbidding abortion in Roe v. Wade. Advocates for family planning were often led by physicians, such as Alan Guttmacher, president of the Planned Parenthood Federation of the United States, and Fernando Tamayo, leader of Profamilia in Colombia.

In the 1960s, demographers and economists warned of adverse effects of rapid population growth on development. Paul Erhlich captured public attention with The Population Bomb (1968). The Rockefeller and other foundations began to fund family planning. The Swedish government offered international
support for family planning, and in the United States General William Draper Jr. persuaded Congress to follow suit.

However, other demographers, such as Kingsley Davis, continued to emphasize socioeconomic development as a prerequisite for smaller families. Gary Becker and others framed decisions about family size as economic decisions based on a rational analysis of costs and benefits of having children. However, given the frequency of human intercourse in relation to conception, the issue is not to decide when to have a child, but how to turn off the possibility of conception, something that can only be done when a couple has ready access to contraception, backed up by safe abortion. Everywhere poor families had more children than rich ones, but the question remained: was this a choice, or did poor people find it more difficult to access contraception and safe abortion?

Those working in the front lines of family planning, led by Reimert T. Ravenholt, the principal administrator in the U.S. Agency for International Development (USAID), believed improving access to fertility-regulating choices was the key to smaller families. He began to implement large-scale programs offering oral contraceptives, IUDs, condoms, and voluntary sterilization as well as initiating surveys of the family planning knowledge, attitudes, and practices of women in developing countries. These surveys have been broadened into Demographic and Health Surveys, and they remain the largest social science surveys ever conducted. Virtually every survey has demonstrated that women are having more children than they intend, and everywhere that realistic family choices were made available, as in South Korea, Thailand, or Mexico, family size fell. Nevertheless, several schools of thought about population continue to compete for intellectual dominance. All are influential in discussions about population, although only those specifically concerned with family planning have put population center stage.

Economists.

Economists have always played an important, although sometimes contradictory, role in establishing intellectual and public policy related to population. Macroeconomic concerns that the investment required to keep pace with rapid population growth would undermine the economic development of poor countries supported family planning policies in the 1960s and 1970s. In a much-quoted article, "The Tragedy of the Commons," Garrett Hardin saw rapid population growth exceeding the carrying capacity of the land. But, accepting then-current ideas about the demographic transition, Hardin concluded that voluntary family planning would not ameliorate the threat. Other experts saw the relationship between population and the environment as so complex that they were reluctant to provide clear-cut conclusions. Julian Simon, Ben Wattenberg, and others argued that increasing population would drive technical ingenuity to substitute new materials for declining resources. In the 1980s, the Reagan administration free-market policies trumped any adverse effects of rapid growth. In the 1990s, the pendulum began to swing back when it was shown that countries that had undergone a rapid fall in birth rates had reaped a "demographic dividend" benefiting their economies.

Equity group.

A politically influential group in population research has been those who argue that attention to population takes attention away from the excessive consumption of the first world, reflecting economic inequity, which is the primary injustice needing remedy. This school of thought was influential at the Rio Conference on population and development (Rio de Janeiro, 1992) and in certain circumstances it is a valid conclusion. In other situations, however, there is little doubt that population growth per se is the key factor. For example, in 2000, 179 million people in Egypt, Sudan, and Ethiopia depended on the Nile, which is almost depleted by the time it reaches the Mediterranean. In 2050, 385 million people will compete for the same amount of water.

Women's groups.

Since the mid-1960s, women's groups have played an increasingly important role in discussions of population. In Europe and North America, they were forceful advocates for access to family planning as essential to female equality and empowerment. However, a subgroup of feminists opposed hormonal contraceptives as unnatural and feminists in India have prevented the use of the popular injectable contraceptive, DepoProvera, and objected to the use of a low-cost, nonsurgical method of voluntary sterilization.

National security.

Rapid population growth is associated with a high ratio of younger to older men, and analysts in both academia and the U.S. Central Intelligence Agency found a relationship between this ratio and civil disturbances, warfare, and terrorism. It is a theme that was taken up in a secret National Security Study Memorandum requested by President Nixon in 1974, which recommended additional support to international family planning. As can happen in a field permeated with emotions and religious beliefs, and thinking that has no evidential basis, lobbying by Catholic bishops successfully blocked implementation of this memorandum, which was only declassified in 1989.

The Vatican.

The Judeo-Christian association of sex with sin goes back to the Adam and Eve myth, but it was St. Augustine's assertion that coitus can be justified only for procreation that underlies Vatican teaching. In the 1960s, many leading theologians, including the commission the pope himself established, argued that sex had a dual purpose—to express love and to procreate—and that contraception could be used to separate the two. The Catholic physician John Rock, who had played a leading role in developing oral contraceptives, argued in The Time Has Come that the pill was morally acceptable because it imitated the natural suppression of ovulation during pregnancy and lactation. However, Pope Paul IV provided the most wrenching twist in the intellectual history of population of the second half of the twentieth century by reiterating the Augustinian interpretation of sexuality in his 1968 encyclical Humanae vitae. In its wake, priests and communicants left the Catholic Church, and those who remained adopted contraception and safe abortion at the same rate as non-Catholics. While the Holy See continues to oppose family planning on the international stage, Italy voted in two referenda for contraception and safe abortion.

Changing Paradigms and Uncertain Policies

The lack of consensus in intellectual thinking, the strength of faith-based assertions about human reproduction, and
competition over limited funds have all fed large and sometimes contradictory swings in domestic and international policies. The first of three landmark decennial international conferences on population in Bucharest in 1974 was summed up by the aphorism that "development is the best contraceptive." Shortly afterward, however, China instituted a one-child policy and India passed (although it was never implemented) a compulsory sterilization law. By the 1984 conference in Mexico City, the developing countries were asking for mainline family support but the Reagan administration proclaimed that free markets trumped the population explosion.

The 1994 Cairo International Conference on Population and Development (ICPD) saw yet another policy change. Some in the women's movement began to portray organized family planning as intrinsically coercive and sought to secure the transfer of international resources to broader aspects of women's health. The ideological shift altered the vocabulary in revealing ways, as gender was substituted for sex and reproductive health replaced family planning. For many, Cairo was an intellectual turning point, but shortfalls in funding have stymied large-scale implementation of the Cairo Program of Action.

The ICPD occurred as the number of AIDS infections was growing exponentially, although calls for action in this area were buried in a plethora of less important issues. In the early twenty-first century AIDS has reached catastrophic levels in some countries, but it will not change the trajectory of global population by much. It has, however, taken priority away from family planning in foreign aid budgets and, as a result, in parts of Africa the trend toward lower birth rates stalled or has been reversed.

In the 1990s, as access to contraception and safe abortion increased in Europe, birth rates fell to below replacement level, while in the rest of the world increases in population fed internal and cross-border migrations, with more and more people crowding into big cities. In 1975, 40 percent of four billion people lived in cities (twenty-six cities had more than five million people); it is estimated that in 2025, of almost eight billion people, 60 percent will live in cities (seventy cities with more five million people). Migration between countries is driven by economic pressures, long exposed borders between high-and low-income regions in North America and Europe, and the relatively low cost of air travel. In Europe, the right of citizens from the British Commonwealth or former French colonies to enter the mother country broke down because of the scale of the populations seeking to migrate. In the United States, policy differences between employers and free-market economists, both endorsing a free flow of labor, and those concerned with the environment remain unresolved.

In the history of ideas about population, abortion has proved the single most divisive topic. Abortion is one way women can limit the number of children they have and an important variable in family size. Globally, it is estimated that, on average, every woman now alive will have one abortion in her reproductive lifetime. Intellectually, the abortion debate has been framed in two ways: either as fetal rights or the mother's right to control her body—a dichotomy that preempts further debate—or as an ethical question of "when life begins." The U.S. Supreme Court, however, concluded "that the right of personal privacy includes the abortion decision, but that this right is not unqualified and must be considered against important state interest in regulation." The abortion debate deeply divides the United States, both because of strongly held religious views and because the Supreme Court, Congress, and state legislators can all set policy. In 1973, Jesse Helms, a conservative U.S. senator from North Carolina, amended the Foreign Assistance Act to exclude any support of abortion, forcing U.S. international family-planning policies into a more conservative mode.

The two most important responses to population growth occurred far outside the Western intellectual tradition. The first was the Chinese one-child policy of 1979, which was driven by intellectual analysis of demographic projections, but the policy encountered much external criticism. Yet, however the policy is viewed, without it, the economic growth in China from the 1990s on could not have happened. The second occurred in the Islamic Republic of Iran, where the average number of children in a family fell from 5.5 in the late 1980s to 2.0, a decline equal to that of China's, but without a one-child policy. The driving force in the Iranian transition was not socioeconomic change, but a national policy to make all methods of family planning widely available. Iran's demographers noticed that their population was growing faster than the economy, and if average family size did not decline, poverty would increase. The country's religious leadership, whose intellectual framework for policymaking in the 1990s was profoundly different from that of Chinese Communism in the 1980s, and totally unlike the Vatican in the 1970s, agreed to family planning if it was for the woman's health.

On the whole, the intellectual history of population in North America and Europe has been disappointing. There has been increasing methodological sophistication combined with an inability to produce an acceptable paradigm of human reproductive behavior. At the end of the twentieth century, discussion of population growth was pushed off the debating table by competing schools of thought. Yet, serious problems remain. Despite well-publicized declines in birth rates, globally there are one million more births than deaths every 110 hours. India has one million more births than deaths every twenty-three days and China (even with its one-child policy) adds one million people every thirty days.

In the history of ideas, interpretations of population change, appreciation of the consequences, and evidence-based rational responses have a long way to go.

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Population

Encyclopedia of the Modern Middle East and North Africa
COPYRIGHT 2004 The Gale Group, Inc.

POPULATION

Demography is crucial to an understanding of economic, social, and political life in the Middle East.

Until the nineteenth century, the Middle East experienced a typical Malthusian demographic system: high fertility outpaced high mortality, but there was occasional extraordinary mortality from warfare, famine, or epidemic disease, particularly bubonic plague. The population grew slowly until one of these demographic crises occurred, dipped sharply, then
began to grow slowly once again. This pattern ended in much of the Middle East during the nineteenth century. Despite minor outbreaks, truly catastrophic epidemics ended with the cholera epidemic of 1865. The increase in central government control facilitated security, trade, and delivery of food to famine regions. Egypt's population began to grow early in the century, as did that of Anatolia and the coastal provinces of Ottoman Syria during the 1870s. Iraq, Arabia, and Iran took little part in either the improvement in civil conditions or population growth.

The period of World War I (and the wars in Anatolia that followed it) was a demographic water-shed in the Middle East, a period of great mortality and forced migration unequalled in the previous millennium. After the war, the Middle East began a new period of population growth, erasing the wartime population losses within a decade. Turkey's population began to expand fairly rapidly, from 14.6 million in 1927 to 18 million in 1940. Egypt's population grew from 13 million inhabitants in 1917 to 16 million in 1937. Other countries grew less quickly, but population increased markedly across the region. Nevertheless, the Middle East can be described as underpopulated before World War II. Large areas of potentially fertile lands were uncultivated. Population density was low, due to high mortality and lack of developed resources. By modern standards, mortality had declined only slowly. In late Ottoman times, mortality had averaged more than 3.5 percent per year. This condition only gradually improved between the two world wars. However, Egypt, Palestine, and Turkey managed to lower mortality through irrigation, public sanitation, and by ending conditions of civil unrest that had diminished the distribution of crops and goods. Medical improvement was a minor factor.

source: projections to 2000 and 2025 from united nations, world population prospects, 2000. (medium-fertility variant)

Table by GGS Information Services, The Gale Group.

1800

32.8

1925

54.7

1825

33.4

1950

79.2

1850

33.8

1975

154.3

1875

36.0

2000

308.6

1900

44.1

2025

449.3

After World War II, as in much of the world, the Middle Eastern population began to increase rapidly. Fertility, always high, remained so, while introduction of modern medicine greatly lowered mortality. Modern agricultural techniques and the new crops of the green revolution increased the ability of Middle Eastern economies to feed larger populations. The result was a population boom. From 1950 to 1990 the population of the Middle East increased threefold. By the 1960s the rate of population increase meant that, if the high rates continued, future populations would double every twenty-five years. These rates of increase put great strain on the economies of the region. The results have included rapid and unplanned urbanization

life expectancy at birth*

1950

2000

1950

2000

* "1950" is actually for the years 1950–1955

** 1950 is average for north and south yemen

source: united nations, world population prospects, 1990; world bank, world development indicators, 2002.

Ttable by GGS Information Services, The Gale Group.

bahrain

51

73

yemen**

33

57

egypt

42

68

oman

36

74

iran

46

69

qatar

48

75

iraq

44

61

saudi arabia

40

73

israel

65

78

syria

46

70

jordan

43

72

turkey

44

70

kuwait

56

77

u.a.e.

48

76

lebanon

56

71

and unemployment, as well as overuse of fertilizers and poor agricultural techniques that temporarily yield large crop increases but eventually exhaust the soil.

Fertility

The average fertility of Middle Eastern women changed little for centuries. Women who lived through their childbearing years (many did not) could expect to have six to seven children (the total fertility rate). Since the late 1970s fertility decreased in most countries. By 1999 the average woman in Turkey had 2.4 children, in Egypt 3.3, in Iran 2.7. However, in Syria and Saudi Arabia, the average remained very high, at 4.6 per woman. Women in Yemen and Oman had 6.2 children on average. Contraceptive usage varies greatly: in 1999, more than 60 percent of Turkish women used some form of contraception at some time in their lives; in Jordan, 27 percent. In some other countries the figures were much lower. Despite recent reductions, the Middle East remains one of the highest fertility regions in the world.

The history of high fertility has strained the capacity of the Middle Eastern economies. Nearly one-half of the population in Syria, Iraq, and Yemen is children under age fifteen. Even Middle Eastern countries with lower fertility, such as Turkey, have populations in which one-third are under fifteen. (This compares with 21 percent in the United States and 20 percent in Western Europe.)

If present fertility trends continue, future Middle Eastern populations will divide into two very different patterns. Israel is already nearing a European pattern of low fertility. Kuwait, Lebanon, Qatar, the Emirates, and Turkey are approaching that standard. Yemen, Syria, Iraq, Saudi Arabia, and others still retain high fertility. The demographics of the latter countries will in fifty years look very different from those of the former, with very large numbers of children and a fast-growing population. For example, at the beginning of the twenty-first century, Syria, Iraq, Jordan, and Saudi Arabia taken together had a slightly smaller population than Turkey. If trends continue, in fifty years they will together have twice as many people as Turkey.

Mortality

In the absence of extraordinary causes, fertility would have always outstripped mortality in the traditional Middle East. The population would have risen at approximately 1 percent per year. In fact, epidemics, wars, and famines meant that mortality equaled fertility. The most common causes of death were gastrointestinal diseases. Infant mortality was particularly high, with more than 40 percent of children dying before their first birthday, more than half before age five. Epidemics of plague and cholera caused temporary high mortality. In Egypt, for example, cholera took more than 100,000 lives in each of the epidemics of 1855 and 1865 and almost 200,000 in 1831. Bubonic plague took 500,000 lives in 1835 alone.

Warfare also caused great mortality in the nineteenth century. The Ottoman wars with Russia were particularly deadly for both military and civilian populations. From the beginning of the Balkan Wars in 1912 to the end of fighting in the Turkish War of Independence in 1922, the region suffered some of the worst wartime mortality in history. The highest death rates were found in eastern Anatolia—the result of war between the Ottomans and Russians and conflict between Muslims and Armenians in western Anatolia after the Greek invasion and in Palestine. In Anatolia, 3.8 million died (22 percent), and in Palestine 50,000 (6 percent). In all those conflicts, starvation and disease took a higher toll than did actual battle. Lebanon also suffered mass starvation during the war.

After World War II, the rapid introduction of modern medicine, public sanitation techniques, and agricultural improvements reduced mortality rates sharply. In 1950 the Middle East had a high crude death rate (deaths divided by total population) of more than 2.3 percent a year, but by 1999 it had fallen to less than 0.6 percent a year. Some countries, such as Egypt (0.7 percent in 1999) and Yemen (1.2 percent in 1999) lagged behind. A major part of the postwar improvement came in infant mortality. In 1950 one in five Middle Eastern children died before age five; in 1999 only one in nineteen died before age five, compared to a world average of one in thirteen.

The Iran–Iraq War of 1980–1988 resulted in the deaths of hundreds of thousands of Iranian and
Iraqi soldiers, with consequent effects on the size and gender structure of both populations. In addition, it is estimated that the Baʿthist regime in Iraq killed some three hundred thousand of its own citizens during campaigns against the Kurds in the north of the country and against the Shiʿa in the south.

The United Nations has lowered its projections of the region's population growth to 2025 as a result of the faster than expected decline in fertility. This has translated into slower population growth rates starting in Egypt and spreading east. The absolute increases in population are still growing in many countries because of past fast growth rates, and it will take ten to twenty years for slower growth rates to translate into smaller absolute increases.

Migration

Refugee migrations have been a major demographic factor during the past two centuries. Only the most prominent population transfers can be mentioned here: During the nineteenth and early twentieth centuries, great population movements took place as direct results of Russian imperial expansion in the Crimea and Caucasus and of nationalistic movements among the Christian peoples of the Ottoman Empire. Russia expelled or caused the migration of approximately 1.2 million Circassian, Abhazian, and Laz Muslims from the lands of the Eastern Black Sea. Of these, 800,000 survived and most eventually settled in what today is Turkey, as did the 300,000 Crimean Tatars forced to emigrate during the 1850s and 1860s. A sizable group of the Circassians were settled in the Arab world. Russian expansion also fostered a century-long population exchange, with much attendant mortality, between the Turks and Kurds of Russian Transcaucasia and the Armenians of Ottoman Anatolia and Iran. Between the 1820s and 1920s, 500,000 Armenians and 400,000 Muslims (not including the Circassians and Abhazians) crossed the borders. During World War I, an estimated one million Muslims were internal refugees in Eastern Anatolia; an estimated 275,000 Armenians were deported to or were refugees in the Arab world, and 135,000 were refugees in Europe and the Americas.

Nearly 600,000 Turks (40 percent of its Turkish population) were surviving refugees from the new state of Bulgaria after the Russian–Ottoman Wars of 1877–1878. Greece, Bulgaria, Serbia, and Montenegro expelled to Anatolia and Eastern Thrace 414,000 Turks during and immediately after the Balkan Wars of 1912–1913. During World War I, the Turkish War of Independence, and the Greek-Turkish population exchange that followed, more than one million Greeks from Anatolia and eastern Thrace went to Greece and 360,000 Turks from Greece to Turkey. Up to 1.5 million Turks were internal refugees within Anatolia and eastern Thrace during the Greek-Turkish war.

Before World War II a major immigration of primarily European Jews swelled the Jewish population of Palestine from 60,000 in 1918 to 600,000 in 1946. More than 700,000 Palestinian Arabs were refugees in the Arab-Israel War of 1948. Between 1948 and 1975, 1.6 million Jews came to Israel. Half of these were from the Middle East and North Africa, another third from Eastern Europe, especially the Balkans. Immigration to Israel has continued recently with nearly one million Jews from Russia and successor states.

The only Middle Eastern country to be heavily affected by refugees from the Afghan War was Iran, which accepted more than two million Afghan refugees. Turkey took in 300,000 ethnic Turkish refugees from Bulgaria, as well as Iranian refugees after the Iranian revolution and Kurdish refugees after the Gulf War. Many of the refugees to Iran and Turkey have been repatriated or have moved to other countries. A significant number of the refugees from Afghanistan, Iraq, and Bulgaria have returned home at least once, only to leave once again when economic and political conditions changed.

The quest for employment has been a major cause of migration into and from the Middle East. In Ottoman times, 175,000 Turkish emigrants went to the United States from 1869 to 1914. More recently,
the International Labor Organization estimated that 1.8 million Turks were working in Germany, the Netherlands, and Belgium in 1988. During the same year, 20,000 Koreans, 50,000 Indonesians, and 90,000 from the Philippines worked in the Gulf states. Before the Gulf War, up to two million foreign workers, mainly Egyptians, worked in Iraq.

Urbanization has been the most significant factor in internal migration in the modern Middle East. Driven by population pressure in rural areas, the urban population increased from twenty-one million (27 percent urban) in 1950 to 185 million (60 percent urban) in 1999. There is considerable variance between countries: In 1990, Syria's population was only half urban, Egypt's less than half urban, while the populations of Iraq and Turkey were more than 60 percent urban. Istanbul was one of the twenty largest cities in the world. Smaller countries such as Israel and Lebanon were as urbanized as Europe or North America.

Censuses and Population Data

A census by definition registers the entire population at one time. Prior to 1882 no real census was taken in the Middle East. In the place of censuses, the Ottoman and Egyptian governments made compilations of registration data. The registers were lists of inhabitants by household in each village, taken by government officials. These often produced surprisingly accurate counts of the population, especially in areas that were under close governmental control. On occasion, the central governments of Egypt and the Ottoman Empire ordered general updates and compilations of the registers. During the 1860s the Ottoman government began to publish population numbers in the salname s (yearbooks) of its provinces. The Ottoman compilations usually listed data by sex and religion only, even though age-specific figures were kept and are available in archives. The 1313 Istatistik-i Umumi ("1895 General Statistics") was the only Ottoman publication to include data by age group. Population data was collected sporadically in Iran, but was not published officially.

The first real census in the Middle East was taken by the khedival government in Egypt just prior to the British occupation in 1882. Under British statistical influence, Egypt published censuses in 1897, 1907, 1917, 1927, and 1937. The British also undertook a limited form of census in Aden (later People's Democratic Republic of Yemen) in 1881, then published other counts of Aden, as part of the censuses of India, in 1891, 1901, 1911, 1921, and 1931. The Turkish republic began a modern census

program with censuses in 1927 and 1935, followed by censuses every five years. The British Mandate government in Palestine took fairly accurate and very detailed censuses in 1922 and 1931, and with limited success updated the census data through birth and death records and published the data in the Palestine Blue Books. The French collected data in Syria and Lebanon, but only published brief summaries that indicate poor recording. An incomplete census was taken in Lebanon in 1942–1943.

Modern Middle Eastern censuses have routinely been supplemented by publications of detailed information on marriage, divorce, birth, and death, although these often have been accurate only for urban areas. Sample surveys of the population, often supported by the United Nations or other international bodies, have also been published.

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population

population. Despite the work of John Graunt, whose Observations on the London bills of mortality came out in 1662, and his friend Sir William Petty, whose Political Arithmetick was published in 1690, little was known for certain in the 18th cent. of the size of the population of Britain or even whether it was increasing or diminishing. Dr Richard Price in 1779, at a time when population growth was accelerating, argued that the population of England and Wales had decreased since the Glorious Revolution. Since the country was at war with France and Price concluded that the French population was rising, this caused much alarm. In the absence of accurate statistics, the debate which followed was bound to be inconclusive. In Parliament it was argued that a census would provide Britain's enemies with valuable information but John Rickman in the 1790s lobbied with success and the first census for England, Wales, and Scotland was held in 1801. In 1821 the first complete census for Ireland was made. Though the census methods were crude by modern standards, the institution of decennial censuses offered a systematic basis for estimates and one which Rickman helped to refine and improve. The publication of Malthus'sEssay on Population in 1798, revised and expanded in 1803, ensured that the subject received great attention for many years. The study of population in all its aspects has become an important branch of historical investigation, particularly since the Second World War, with the foundation of the journal Population Studies in 1947 and the establishment of the Cambridge Group for the History of Population and Social Structure in 1964.

Three broad generalizations may be offered. First, that the population history of the four peoples of the British Isles has been different and that there have been marked divergencies and changes within each group. Second, that until the late 18th cent. the population was small, with considerable fluctuations dependent upon the birth and death rates, harvests and famines, plague and warfare, immigration and emigration. From the late 18th cent., there was a sudden acceleration of growth until parts of England, the central region of Scotland, and parts of south Wales became among the most densely populated areas of Europe. Third, that in England, the growth of London from Tudor times was so rapid that it forms, in itself, a special factor.

Very few conclusions have been agreed about the population of the British Isles before the Norman Conquest. Large-scale migrations of Angles, Saxons, Jutes, Danes, and Norsemen, and substantial movements between Ireland, Scotland, and Wales, make estimates very hazardous. The population of Roman Britain remains highly conjectural with a disturbing divergence of scholarly opinion between 1 million and 6 million for the later 2nd cent. It has been suggested that London may have had 30,000 inhabitants, Colchester and Cirencester 15,000, Lincoln and Gloucester 5,000, and the remaining towns between 2,000 and 3,000. A figure of 20,000 has been proposed for Wales, though there is no way of checking it. Nor is it easier to offer figures for the subsequent Saxon period, since we cannot be sure to what extent devastation and warfare were offset by new arrivals. The consensus puts the figure for England towards the end of the Saxon period at about 1½ million, which would suggest a substantial decrease from later Roman times, and the towns significantly smaller—London at 12,000, York 8,000, Norwich and Lincoln 5,000. The most prudent historians of Ireland and Scotland refuse to suggest or endorse any estimates for those countries.

There is little disagreement that the population of England increased greatly between 1066 and the plague disasters of the mid-14th cent., though much less agreement about the exact figures. If the estimates for William I's reign, based on Domesday Book returns, are correct, the population was about 1½ million and had more than doubled by 1300 to about 4 million. This was part of a general European pattern, assisted in England after the Conquest by the absence of major invasions and a lessening of internal conflict. The increase had almost certainly slowed by the time the Black Death struck, since the early 14th cent. saw adverse climatic changes and a pressure on subsistence which produced periodic famine. Plague then struck four times between 1349 and 1375 with devastating consequences. Estimates of mortality may be inferred from the death of clerics, which is recorded, and by information from particular villages or estates. But each source of evidence is open to hazard. The clergy as a profession might be unduly at risk from their obligation to visit and succour victims and therefore the 50 per cent death rate in the dioceses of Exeter, Winchester, Norwich, and Ely may not have been replicated in the country at large. Similarly, though all twelve of the bishop's villeins at Cuxham in Oxfordshire perished from plague in 1349, there were other villages and areas comparatively little affected. In short, it seems that over 40 per cent of the population died, with profound political and economic consequences. The Black Death also visited Ireland, Wales, and Scotland. Only in Scotland does the mortality seem to have been significantly lower, perhaps because the plague was at its most deadly in crowded towns and ports.

Recovery from the Black Death and its later visitations was slow. The population of England may have been reduced to about 2½ million. The poll-tax returns for 1377 have been employed to suggest total numbers, with the usual difficulties, but at least offer evidence on population distribution: East Anglia and the east midlands were most densely populated, the north and west much less so. Not until the middle of the 15th cent. did the rate of increase pick up and even then it was patchy. But during Tudor times, the population reached its pre-plague position and by the end of the 16th cent. stood at just over 4 million. Rickman, in an analysis of parish register returns, printed a preface to the 1841 census suggesting a figure of 4.3 million for 1600. The population of Ireland was about 1 million, that of Scotland perhaps a little less, with more than half of the inhabitants north of the Tay. Wales was still very thinly populated with about 350,000 people: Carmarthen, the largest town, had no more than 2,000 people—less than one-hundredth of the size of London—and followed by Brecon with 1,750. Elsewhere the size of towns was beginning to increase. At over 200,000 London was already the largest town in western Europe and outstripping all its rivals. The population of Norwich was about 15,000, Bristol and York about 12,000, Newcastle and Exeter, around 10,000—all of them important provincial centres and with good water communications.

From the 17th cent. the sources for demographic study improve. Thomas Cromwell ordered the keeping of parish registers from 1538, but many incumbents did not at first do so, and some registers have been destroyed by fire, flood, wars, and mice. They are augmented from 1629 onwards by the regular London bills of mortality. The high Tudor growth rate was not sustained throughout the whole 17th cent., when emigration, civil war, and plague dampened the increase. The population of England and Wales rose to about 5.4 million by 1656 and then steadied, or even declined slightly. The population of Wales cannot have increased greatly and by 1700 may have been 400,000. Scotland was affected by plague in the 1640s, heavy emigration to Ulster, and by severe famine in the 1690s. Its population in 1700 was probably little higher than in 1600: Edinburgh, by far the largest town, had between 30,000 and 40,000 people. Despite heavy warfare, the Irish population may have doubled by 1687 and reached well over 2 million by 1700, with Dublin beginning to grow rapidly. London continued to grow disproportionately, had reached half a million by 1700, and was larger than all the other urban centres together. Of great political importance for the future was the expansion of the American colonies, at about 250,000 by 1700, of whom some 10 per cent were negroes: New York, Boston, and Philadelphia were already sizeable towns, edging towards 10,000.

There were few indications at the beginning of the 18th cent. that the British Isles were on the threshhold of a population explosion. Population increase had, if anything, slowed down, though the country had recovered from the ravages of the Black Death. The causes of the acceleration have been extensively debated. The establishment of voluntary hospitals and improved methods of combating smallpox were bound to be slow in their effect since they did not operate much outside urban areas. Plague at last disappeared, though contemporaries could not be certain that it would not return. Agricultural yields were improving and the development of turnpike roads and canals later in the century enabled food to be transported more quickly to areas of shortage. But any explanation must have a European dimension since the increase was a general one. The early view that the population rise was largely due to a falling death rate has been increasingly challenged, partly because the increase accompanied widespread urbanization and 18th-cent. cities were by no means healthy places. More emphasis is now placed upon a significant rise in fertility rates, as a result of people marrying earlier, and because a smaller proportion of the population remained unmarried. The move to towns may have freed young men to marry, since their labour was no longer needed on the family farm which could not support several households.

Though the causes of the great acceleration are still far from agreed, the consequences are clear. From the 1740s onwards, the population began to rise, not to fall again as it had so often in the past, but a sustained and incremental growth. From 5.7 million in 1750, the population of England reached 8.6 million by 1800 and 16.5 million by 1850. The Scottish population also grew, particularly in the industrial and trading towns of the central region, though less rapidly than that of England—from 1.2 million in 1750 to 1.6 million by 1800 and 2.8 million by 1850. But the most startling increase was in Ireland, where from about 3 million in 1750, it reached 5 million by 1800, and in 1845, on the brink of the famine, stood at well over 8 million, dangerously dependent on the potato harvest.

The Irish famine, from 1845 to 1848, was a unique event in modern European demography and its effects comparable to those of the Black Death. One million people died of starvation and disease, the birth rate fell, and there was a large-scale exodus, mainly of younger people, in the decades after the disaster. Well over a million people left Ireland in the 1840s, another million in the 1850s, and 850,000 in the 1860s—mainly for North America, and especially from Munster and Ulster. Co. Clare, with 286,000 people in 1841, had 85,000 100 years later. The Irish population was down to 6.5 million by 1851, 5.8 million by 1861, 4.4 million by 1901. A hundred years after the famine, it stood at 4.3 million, just over half what it had been in 1845.

In the rest of Britain, the sustained growth was felt in every part of public life. Internationally, it changed Britain's relative position. In 1550 the population of Spain and Portugal was double that of the British Isles: by 1914 the position was reversed. Just before 1914 the population of the United Kingdom passed that of France. But of greater long-term significance was the transformation brought about from the 17th cent. onwards by emigration, which brought into being the USA, Canada, Australia, and New Zealand and effected a fundamental shift in world power. At home, despite Malthus's fears of extra mouths to feed, agricultural improvements meant that fewer farm labourers could support more and more factory workers. The increase provided labour for the industrial expansion and purchasing power to sustain it. The internal balance of England shifted as the great industrial towns of the north developed. In Scotland, Glasgow rose from a town of 10,000 in 1688 to a conurbation of a million in 1901: in Wales, the balance of population moved to the mining areas of the south and Cardiff, a town of 1,800 people in 1801, had 128,000 inhabitants by 1901. The old electoral system, with its little Wiltshire and Cornish boroughs, looked increasingly absurd after 1801, when the census revealed that three of the six largest English towns—Manchester, Birmingham, and Leeds—had no MPs at all. The shift of power to the north after the Reform Act of 1832 and the Municipal Corporations Act of 1835 gave vast influence to the dissenters, who dominated towns like Bradford, Leeds, Manchester, and Halifax. The churches found their urban parishes swelling out of control, and there were massive building efforts by the dissenters in the earlier 19th cent. and the Anglicans in the later.

The population of England and Wales continued to rise in the 20th cent., though at a reduced rate. By 1996, England and Wales totalled 50 million, Scotland 5 million, Northern Ireland 1½ million, and Eire 3½ million. England became by far the most densely populated of the major European powers—four times the density of France, and on a par with Holland and Belgium. From this stemmed many social problems: of law and order, bearing in mind that a second-division football match in the 1990s might well attract a crowd twice the size of the second largest city of Stuart England; of traffic jams, road rage, and general transport policy; of noise pollution and broader environmental questions. The slowing down of the birth rate after the Second World War meant an ageing population, with heavy demands on medical care and for pensions. The general movement out of older towns led to the problem of decaying city centres. Substantial immigration from the Commonwealth in the 1950s and 1960s produced suburbs and, in some cases, whole towns where the character of the community had changed. Though demography is a rarefied and demanding discipline, its implications are profound.

J. A. Cannon

Bibliography

Connell, K. H. , The Population of Ireland, 1750–1845 (1950); Flinn, M. W. (ed.), Scottish Population from the Seventeenth Century to the 1930s (Cambridge, 1977); Houston, R. A. , The Population History of Britain and Ireland, 1500–1750 (1992); Vaughan, W. E., and Fitzpatrick, A. J. (eds.), Irish Historical Statistics: Population 1821–1971 (Dublin, 1978); Wrigley, E. A., and and Schofield, R. S. , The Population History of England, 1541–1871 (Cambridge, Mass., 1981).

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Population

Pollution A to Z
COPYRIGHT 2004 The Gale Group Inc.

Population

Throughout most of human history, the world's population has grown gradually. It took thousands of years for the global population to reach one billion people (around 1800). Then, in a little more than a century, the population jumped to two billion (by 1960), and to three billion by 1980. In just twenty years—between 1980 and 2000—the world's human population doubled from three billion to six billion people.

The human population explosion during the past century was the result of several factors. Fertility rates remained high, while medical and agricultural advances such as antibiotics, immunizations, clean water, and improved food availability reduced mortality rates—especially among infants and children.

It is difficult to predict how rapidly the human population will continue to increase, due to the many factors that affect population growth. Another important question that scholars ask is "How many people can the earth support?" While the human population grows, the earth's size and resources remain the same. Technology can increase the amount of food that can be produced on a piece of land, but it cannot increase the amount of land and water on the planet. Many people regard population growth as the single most serious global issue, because population size is closely linked to environmental and human health conditions.

Environmental problems are aggravated by population explosions. More people means more resources and energy are consumed and more pollution is created and more waste is sent to landfills. More land is needed to grow crops and build houses. More trees are cut down for new homes. More cars are built, more fossil fuels are used, and more gases are released into the environment. More natural wilderness areas or beautiful landscapes are destroyed to provide resources and cropland. In short, population growth makes other environmental problems harder to solve.

Projecting Population Change

Scholars have spent centuries trying to find reliable ways to predict population change. One of the most famous population researchers was Thomas Malthus, a British clergyman who studied population growth in the 1770s. In
his famous 1798 Essay on the Principle of Population, Malthus argued that human populations tend to grow exponentially, while food production is limited by land available for agriculture. In short, human populations tend to increase faster than food supply, leading to an imbalance.

Malthus projected that population increases in England would quickly outstrip the available food supplies, leading to famine and misery. Malthus's predictions for England never occurred in his lifetime. England's population did increase, but advances in science and technology enhanced food production. Malthus's theory also failed to take into account colonial growth as a result of other factors. Still, scholars use Malthus's concepts of geometric population growth today, though new models of population change are far more complex.

Researchers who study population change consider many factors for each country. Population change for any group of people is determined by fertility, mortality, and migration rates. What is the average number of children per family? What is the life expectancy? Are people migrating into or out of a country? Each of these is, in turn, affected by other factors.

It is important to remember that population projections are just estimates based on past information; they do not account for unknowns such as future wars, epidemics, or the effects of climate change. However, the scholars who make the projections attempt to improve their accuracy by revising projections as new information is collected. The United Nations Population Division is one of the organizations responsible for making population projections. After considering the potential impact of the current AIDS epidemic, the United Nations recently lowered its population projection for 2050 by more than one billion people.

United Nations Projections

At the beginning of the twenty-first century, the world population is still growing at a rate of 1.2 percent annually. This is the same as adding 77 million people (roughly the population of France) to the world each year. A world population projection published by the United Nations in 2002 estimates that the world's human population will reach 8.9 billion by 2050.

This population increase is not expected to occur evenly across the globe. The populations of some nations are shrinking while those of other nations are swelling. During the past few decades, reproduction rates have decreased in countries where the standard of living has improved; these improved living standards are generally associated with higher education levels across a population and access to birth control. Today, as many as thirty-three countries are witnessing population declines due to lower birthrates. Japan, Bulgaria, Italy, Bulgaria, Estonia, and the Russian Federation are among the countries that have achieved negative population growth.

Population explosions tend to occur in regions already struggling with hunger. Africa is expected to undergo the most rapid growth, increasing from 784 million people in 2000 to nearly 1.8 billion in 2050. Eight countries—India, Pakistan, Nigeria, the United States, China, Bangladesh, Ethiopia, and the Democratic Republic of Congo—are expected to account for half of the world's population increase during the next fifty years. India may overtake China as the most populous country, rising from just over one billion to more than 1.5 billion between 2000 and 2050. Birthrates are not the only reason for the anticipated rises. The United States has a low birthrate, but a high immigration rate.

How Many People Can the Earth Support?

Is there a limit to the number of people the world can support? Some people contend that new technologies will make it possible for the earth to support ever-larger human populations. They describe the earth's resources as virtually inexhaustible, due to the potential of technology. They point to the scientific advances that helped increase crop yields across India and China as an example of the human ability to adapt through technology.

Other scholars believe that there are limits to how much technology can accomplish. They argue that the earth's capacity to support human population growth is finite—because natural resources can be damaged or depleted. For example, India's increased crop production has not keep pace with its growing population. India's per-person food production is actually dropping as the food supply is shared among more and more people.

Water shortages may be the most insurmountable obstacles for human survival, as populations continue to grow. On every continent (including North America), rising demands for water are already causing water tables to drop to dangerously low levels, depleting future water supplies. Several of the world's major rivers are being drained dry before running their courses. Most of this water is used for irrigation (to grow food); less is used for industry and domestic use.

Water scarcity is already a serious survival problem for people living in the more populous and arid regions of the world. Scholars predict that most of the world will face water scarcity as human demands on the earth's resources continue to rise. Despite hope for technologies such as desalinization to solve the world's water shortages, the prospects to solve global problems are unlikely. So far, desalinization is too expensive for most nations.

A second challenge the world faces is food production. There is hope that breakthroughs in plant genetics and other sciences will continue to improve food production. Yet many scholars argue that even the most remarkable advances in agricultural technology, aquaculture, and ranching could not raise food production enough to meet the world's growing needs. Food production is also limited by the availability of fresh water and land that can be farmed—two finite resources.

Malnutrition is already a growing problem in many regions that depend on grains. Likewise, countries that depend on fish as a primary protein source are also faced with shrinking food supplies as the world's fish populations are further depleted.

Impact on Human Health and the Environment

Population growth affects almost every element of human health and the environment by exacerbating preexisting problems. For example, if a nation is already struggling to provide food, education, and healthcare to its people, the needs of an even larger population may exhaust the nation's ability to provide for anyone. As a result, the rate of poverty, homelessness, and disease are likely to rise. In most cases, rapid population growth results in a decline in human living standards.

The impact of human population on the environment is complex. A popular theory is that the degree of human impact on the environment is determined by three factors: population size, how much each person consumes, and how much waste each person produces. India may have a much larger population than the United States, but people in United States tend to consume and waste far more goods than people in any other part of the world. According to this theory, a rise in the U.S. population would have a greater impact on the environment than would a similar increase in India's population.

What Is Being Done?

There are many views on what to do about global population growth. Several advocacy groups, such as Negative Population Growth, Zero Population Growth, Planned Parenthood, and the Carrying Capacity Network, focus on raising public awareness about birth control and the need to lower fertility rates. At least one group (Negative Population Growth) advocates that the U.S. government should provide incentives for smaller families and should limit immigration in the United States. The world's most populous country, China, has been exploring a variety of laws and incentives to limit urban families to one child per family, with the goal of reversing the country's unsustainable population growth. However, due to the government's inability to restrict family size in rural areas, where the overwhelming majority of China's population lives, and other factors, China's population growth is not expected to turn around until at least 2020.

Slowing population growth is also a priority for many environmental organizations, including the National Audubon Society, the Sierra Club, the Wilderness Society, the National Wildlife Federation, and the Environmental Defense Fund. Most of these groups have policy statements and/or education programs that deal with population issues.

Bibliography

cohen, joel e. (1995). how many people can the earth support? new york: norton.

internet resources

united nations population division. world population prospects: the 2002 revision population database. available from http://esa.un.org/unpp/sources.html.

Corliss Karasov

—Thomas Robert Malthus, An Essay on the Principle of Population, (1798)">

"Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will show the immensity of the first power in comparison of the second."

—Thomas Robert Malthus, An Essay on the Principle of Population, (1798)

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population

The Columbia Encyclopedia, 6th ed.

Copyright The Columbia University Press

population, the inhabitants of a given area, but perhaps most importantly, the human inhabitants of the earth (numbering about 7 billion in 2012), who by their increasing numbers and corresponding increasing needs can seriously affect the global ecosystem.

Population Growth

History and Evolution

General population increase in the world was negligible until the Industrial Revolution. From the time of the Roman Empire to the colonization of America, the world population grew from about a quarter billion to a half billion persons. By the early 19th cent., however, it had grown to one billion, and subsequently rose to more than 2 billion by 1930, 3 billion by 1960, 4 billion by 1975, more than 5 billion by 1990, and more than 6 billion by 2000; the United Nations estimates the world population will peak at about 10 billion around 2100. In world terms, the population is growing at about 1.2% annually (compared with 0.1% in ancient times and a rate of 1.75% as recently as the 1990s) in population. Although a 1.2% growth rate may appear small, it annually adds some 77 million persons to the world's population, with nearly all of this growth taking place in less developed nations (as it has since the 1950s).

During the Industrial Revolution, advancements in sanitation, technology, and the means of food distribution made possible a drop in the death rate so significant that between 1650 and 1900 the population of Europe almost quadrupled (from about 100 million to about 400 million) in spite of considerable emigration. As the rate of population growth increased, so did concern that the earth might not be able to sustain future populations. The phenomenal increase in numbers led Thomas Robert Malthus to predict that the population would eventually outstrip the food supply. Karl Marx emphatically rejected this view and argued that the problem was not one of overpopulation but of unequal distribution of goods, a problem that even a declining population would not solve.

Modern Population Growth

In the late 20th cent., a major population difference arose in the comparative growth rates of the developed (0.6%) and developing (2.1%) nations. Africa's annual growth rate is about 3%, compared to 1.7% for Asia, 0.7% in Latin America, and 0.3% in Europe. If current rates hold steady, many developing countries will double their populations in 25 years or less, compared to 50 years or more for industrialized nations. Great Britain, for example, has a present doubling rate of 140 years, while Costa Rica has one of 19 years.

Great Britain has accomplished what is known as demographic transition, i.e., it has moved from a condition of high birthrate and high death rate (before the Industrial Revolution), to one of high birthrate and low death rate (during industrialization), and finally to one of low birthrate and low death rate (as a postindustrial society). Most of the countries in the Third World are in a condition of high birthrate and declining death rate, contributing to what is known as the population explosion.

Population Control

A declining birthrate depends to a large extent on the availability and use of birth control and on high living standards that make unnecessary the production of additional children to provide necessary and inexpensive labor. Family planning is national policy in many industrial countries, such as Japan and most of Europe. As a result, in most cases the birthrate has declined. Many developing countries have followed the lead of India (which has since 1952 conducted an extensive, but not totally successful, birth control program) in trying to promote family planning as national policy. These countries include China, Kenya, Pakistan, Taiwan, Turkey, Egypt, and Chile.

In the United States, aspects of the population question, such as birth control and abortion, are among the most bitterly debated subjects. The United States has opposed at times the use of foreign aid appropriations for family planning overseas; domestic family planning is mainly run by private groups such as Planned Parenthood.

A number of nongovernmental organizations concerned with population growth have also appeared. Zero Population Growth, an educational group founded in 1970, aims to stop population growth, first in the United States and then in other countries. On the international level, besides the International Planned Parenthood Federation, the United Nations Economic and Social Council provides birth control aid to underdeveloped nations.

Bibliography

See D. Glass and D. Eversley, Population in History (1965); W. D. Borrie, The Growth and Control of World Population (1970); N. W. Chamberlain, Beyond Malthus (1970); D. Fraser, The People Problem (1971); P. Hauser, Population and the Urban Future (1982); K. Davis, Resources, Environment and Population (1991).

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population

population In statistical terms, a population refers to the aggregate of individuals or units from which a sample is drawn, and to which the results of any analysis are to apply–in other words the aggregate of persons or objects under investigation. It is conventional to distinguish the target population (for which the results are required) from the survey population (those actually included in the sampling frame from which the sample is drawn). For practical reasons the two are rarely identical. Even the most complete sampling frames–electoral registers, lists of addresses, or (in the United States) lists of telephone numbers–exclude sizeable categories of the population (who fail to register to vote, are homeless, or do not possess a telephone). Researchers may sometimes deliberately exclude members of the target population from the survey population. For example, it is standard practice to exclude the area north of the Caledonian Canal from the sampling frame for national sample surveys in Great Britain, on the grounds that the Northern Highlands are so thinly populated that interviews in this area would be unacceptably expensive to obtain. However, for most sociological purposes, this particular gap between the target and survey populations is not deemed to be significant—although, in a survey of ‘attitudes to public transportation in thinly populated areas’, it would clearly be problematic. See also STATISTICAL INFERENCE.

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Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

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population

pop·u·la·tion
/ ˌpäpyəˈlāshən/
•
n.
all the inhabitants of a particular town, area, or country:
the island has a population of about 78,000. ∎
a particular section, group, or type of people or animals living in an area or country:
the country's immigrant population. ∎
the specified extent or degree to which an area is or has been populated:
areas of sparse population. ∎
the action of populating an area.
∎ Biol.
a community of animals, plants, or humans among whose members interbreeding occurs.
∎ Statistics
a finite or infinite collection of items under consideration.
∎ Astron.
each of three groups (designated I, II, and III) into which stars can be approximately divided on the basis of their manner of formation.

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Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

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population

population (in ecology) 1. A group of individuals of the same species within a community. The nature of a population is determined by such factors as density, sex ratio, birth and death rates, emigration, and immigration.

2. The total number of individuals of a given species or other class of organisms in a defined area, e.g. the population of rodents in Britain.

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Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

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Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

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Notes:

Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.

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population

population A group of organisms, all of the same species, which occupies a particular area. The term is used of the number of individuals of a species within an ecosystem, or (statistically) of any group of like individuals. See also ecotype.

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Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

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Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.

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population

population A group of organisms, all of the same species, that occupies a particular area. The term is used of the number of individuals of a species within an ecosystem, or (statistically) of any group of like individuals. See also ECOTYPE.

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Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

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Notes:

Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.

In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

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Notes:

Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.

In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

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American Psychological Association

Notes:

Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.

In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.